CA1216111A - Optical device including birefringent polymer - Google Patents

Abstract

ABSTRACT
Optical devices including a molecularly oriented highly birefringent polymer are disclosed. The devices include molecularly oriented polymers comprising recurring units which cxhibit a distribution of high electron density about the long axes of the polymer and the recurring units thereof. Transparent birefringent polymers comprising a plurality of recurring units having a substantially cylin-drical distribution of electron density about the long axis of such units and the chain-extended polymers are included in optical devices and articles. The polymers exhibit high birefringence and simulate in a polymer the optical properties of a uniaxial crystal.

Description

637~

BACKGROUND OF THE INVENTION
This invention relates to an optical device or article. More particularly, it relates to such an article or device including a molecularly oriented highly birefringent polymeric material.
Materials having a birefringent character have been variously applied ill connection with -the construction of filter and other optical devices. Frequently, a birefringent element utilized in an opt eel filter or other device will comprise a plate made from a monocrystalline form of biro-fringent material. Single crystals are expensive materials and are not readily formed to the desired shape or conformation required in particular applications. The size to which crystals can be grown represents an additional limitation on the utile-lion of such materials in optical devices.
Optical devices including a birefringent material in the form of a polymeric layer, such as may be formed by the unidirectional stretching of a suitable polymeric material, have also been described. Thus, light-polarizing devices -;
utilizing a polymeric birefringent layer have been described in US. Patent 3,213,753 (issued October 26, 1965 to H.G.Rogers).
Optical devices including polymeric birefringent materials have so been set forth, for example, in US. Patent 3,506,333 issued April 14, 1970 to E. H. Land) and in US. Patent 3,610,729 (issued October 15, 1971 to Erg Rogers). Frequently, the efficiency of an optical filter, polarizing or other optical device including a birefringent element or layer will pod upon the realization of large net differences in aye en between a birefrin~ent malarial and adjacent or contiguous layers. In general, such net differences will ¢

be maximized where a birefringent material is highly biro-fringent. Correspondingly, large net differences in refractive indices of contiguous layers will be unattainable where biro-fringent polymeric materials otherwise suited to application in an optical device tend to exhibit either low or only marginal birefringent character. Accordingly, optical devices including polymeric layers or elements exhibiting a highly birefringent character will be of particular interest for optical applications and enhanced efficiency.
O SUMMARY OF THE INVENTION
The present invention provides an optical device or article Nash includes a molecularly oriented and optically uniaxial highly birefringent polymer. The polymer comprises repeating molecular units exhibiting high electron density substantially cylindrically distributed about the long axis of the polymer and the repeating units thereof. It has been found that the birefringent character of a polymer is importantly related to the molecular configuration or structure of the repeating units of the polymer and to the distribution O of electron density about the long axis of the polymer and the repeating units thereof. Thus, it has been found that the provision, in a transparent polymeric material comprising a plurality of repeating units in chain-extended relationship, of a substantially cylindrical distribution of electron density about the long axis of the polymer permits the realization of high birefringence and the simulation in a polymeric material of optical properties of a uniaxial crystal. I-The present invention, thus, provides an optical device or article including a transparent molecularly 3 oriented highly birefringent polymer, said highly birefringent polymer comprising repeating molecular units exhibiting high electron density substantially cylindrically distributed about the long axes of the polymer and the repeating units thereof, said highly birefringent polymer being optically uniaxial exhibiting only two indices of refraction. It has been found that birefringence of a polymeric material useful in articles or devices of the present invention exhibit biro-fringence in relation to the molecular configuration of the repeating molecular units and the cylindrical or ellipsoidal electron density distribution about the axes of the polymer and o the recurring units thereof, said birefringence being in relation to said molecular configuration and said electron density distribution according to a dimensionless geometric index G represented by the relationship G - 0.222 x E x D
wherein E is a dimensionless eccentricity factor defined by the relationship 1 + e where en is the longitudinal eccentricity of the polarizability of the repeating molecular unit and eta is the transverse O eccentricity of the electron pursuability of the repeating molecular unit, L is the length of the repeating molecular unit along the Cain axis thereof and D is the mean diameter of the repeating molecular unit.
A preferred article of the present invention is a multi layer light-transmitting device including at least one additional transparent layer hazing an index of refraction substantially matching one index of refraction of said layer of transparent molecularly oriented highly birefringent polymeric material and comprising isotropic or birefringent material; said ) at least one additional transparent layer, when a layer of biro-fringent material, having one index of refraction thereof I

--I-- t.. _ ., .

substantially different from one index of refraction of said layer of transparent molecularly oriented highly bixefringent polymeric material and having a molecular orientation substantially perpendicular to the molecular orientation of said molecularly oriented highly birefringent polymeric material.
THE DRAWINGS
Fig. 1 is a geometric representation of molecular dimensions of a repeat unit of a polymeric material.
Fig. 2 is a cross-sectional view along the line 1-1 of Fig. 2.
Fig. 3 is a vectorial representation of bond and group polarizabilities of a repeat unit of a polymeric material.
Figs. pa and 4b show, respectively, ellipsoidal and circular cross-sectional distribution of electron density about the long axis of a recurring unit of a polymeric material.
Fig. 5. is a diagrammatic fragmentary edge view of a light-transmitting device of the present invention illustrating the transmission of light rays there through.
Fig. 6 is a diagrammatic side view of an automotive vehicle headlamp which includes a light-polarizing filter of the invention.
Fig. 7 is a diagrammatic fragmentary edge view of another embodiment of the present invention showing incident light thereon being partly transmitted and partly reflected as separate linearly polarized components vibrating in ortho-gonad directions.
Fig. 8 is a diagrammatic side view of an optical beam-splitter device including a bire~ringent polymeric material.
DETAILED DESCRIPTION OF THE INVENTION
o As indicated herein before, the present invention provides an optical device including a transparent, molecularly oriented and highly birefringent polymeric material. The biro-fringent polymeric material of the devices of the invention comprises repeat molecular units which exhiklt high electron density substantially cylindrically distributed about the long axes of the polymer and the repeat units thereof. The polymeric material, comprised of repeating units of molecular structure such as to provide a substantially cylindrical distribution of electron density about the long axis or backbone of the polymer, exhibits optical anistropy ox birefringence in accordance with the relationship G c 0~222 ( 1 -I eta ) D
where G represents the geometric index of a repeating unit;
en is the longitudinal eccentricity of the electron polarize-ability of the repeating molecular unit; eta is the transverse eccentricity; L is the length of the repeating unit along the main axis thereof; and D is the mean diameter of the repeating molecular unit. The contribution to birefringence of the molecular structure of a repeating, chain-extending unit and of electron density distribution will be better understood by reference to the drawings hereof.
In Fig. 1 is shown a geometrical representation of a repeating chain-extending molecule-- unit of a polymeric material. Each repeating unit may thus be visualized as a repeating rod-like segment of finite length L and of a generally cylindrical configuration. Birefringence has been found to be importantly related to the molecular structure of the repeating units of the polymer in accordance with the relationship of geometric index G, set forth herein before. A
highly birefringent polymeric material useful in the optical I devices hereof will thus comprise a plurality of molecular units n chain-extended relationship, each unit having a length L, shown in Fig. 1. The long axis X of each repeating unit forms, in the chain-extended polymer, the long axis or backbone. Each axis in Pig. 1 forms a right angle with respect to any other axis The mean diameter D, sex forth in the geometric index G, is determined for each repeating unit by the expression Y + Z
D = 2 . In Fig. 2 is shown along line 1-1 of Fig. 1, a cross-sectional view. The shown Y and Z axes are at right angles to one another, the X axis comprising the axis of the cylinder extending in a direction normal to the plane of the paper.
In addition to a rigid rod-like geometry in a polymeric material as the result of an end-to-end combination of repeating units, the electron density distributed around the long axis of the polymer, variously treated as a cylindrical or ellipsoidal distribution, is believed to comprise a major contributing factor to optical an isotropy or birefringence.
sigh electron density substantially cylindrically distributed around the long axis of a polymer is exhibited, for example, in a polymer of coaxially-bonded repeating units comprising non-coplanar, particularly orthogonal, biphenyl groups. An ortho-gonad relationship between adjacent phenylene rings can be nearly attained by the placement of substituents with large steno effects on at least one ortho-position of each rink, relative to the inter-ring bond. In Fig. 3 is shown a vectorial reps-sensation of bond and group polarizabilities of a repeating I unit of a polymer. It will be appreciated that electron density distribution about axis X will be variously treated as a cylindrical or ellipsoidal distribution depending upon the relative magnitudes Okay the Y and Z vectors. In Fig. pa is shown an ellipsoidal cross-section along the axis of Fig. 3 where the magnitude of the shown Y vector is greater than that of the Z vector. Ideally, Y and Z vectors would be equal and the resulting circular cross-sectional distribution along the X axis is shown in Fig. 4b.

By a combination of lonc3itudinal eccentricity (eland transverse eccentricity (eta), based upon bond and group polaxizabilities, and the length and mean diameter of a repeating unit, a geometric index, G, related lo optical an isotropy or birefringence, can be represented as follows:

G = 0.2~2(-1 +- eta D

wherein elm eta L and D have the monks herein before ascribed.
Longitudinal eccentricity en may be represented according to the following relationship ~X2 _ (~) Transverse eccentricity eta may be represented by the relationship r--2 2 Lo Z
eta y wherein the magnitude of vector Y is the larger of the Y and Z vectors. Ideally, transverse eccentricity eta will equal zero and longitudinal eccentricity en will equal one, in which case, eccentricity factor, E, will equal the theoretical maximum ox two.
Geometric index G can be calculated for a variety of repeating units of a polymer material by resort to mean diameter and length values and longitudinal and transverse eccentricity values calculated from experimentally determined . . , dihedral angles. It will be appreciated that the magnitude of values of length, mean diameter, longitudinal eccentricity and transverse eccentricity will mate~ialltyinf7uence the value ox geometric index G. Thus, it will be appreciated that a repeating unit having, for example, a length of about twice that of a repeating unit having a different molecular structure end con-fiqura~ion will have a geometric index of about twice that of such different repeating unit. Accordingly, in making compare-sons of geometric indices and magnitude thereof in relation to structural differences between comparative molecular repeating units, such differences in length should he borne in mind.
In general, experimentally determined values of birefringence for polymeric materials comprised of repeating units as aforedescribed will correlate directionally with values of geometric index, G, of the repeating units. Thus, in general, recurring units having higher geometric index values provide polymers exhibiting higher birefringence. Polymeric materials comprised of repeating units having a geometric index value, G, of about OHS or higher exhibit high birefringence and can be utilized in the optical devices of the present invention. It will be preferred, however, that polymeric materials comprising repeating units having geometric index values of one or higher be utilized herein. Especially preferred herein are polymers comprising repeating units of geometric index value of 1.2 or higher. Experimentally determined birefringence values for polyp metric materials have been found to correlate with calculated geometric indices. For example, a geometric index of 1.20 was calculated or the recurring structural unit of the following polymer:
H O H H

Theoretical maximum birefringence (I Max) was obtained ox plotting the orientation function for the polymer (calculated from infrared dichroism) against the measured birefringence of the polymer and extrapolating to 100~ orientation. A Max value of 1.20 was obtained. In like manner, a correlation of geometric index 5 of 1.18 and ma of 0.98 was obtained in connection with the following polymer comprising the shown recurring uric L N
CF3 n A number of polymeric materials comprising recurring units having a geometric index as herein before refined of about 0.5 or higher can be suitably employed in oriented form as a birefringent polymeric material in an optical device of the present invention. Rigid rod-like polymeric materials comprised of recurring or repeating diva lent units having inter-bonded p-phenylene moieties of non-coplanar molecular configure-Zion are especially suited herein and are generally characterized by geometric index values of one ox greater an by high biro-ingenue. Exemplary of recurring units of high geometric index and high birefringence are certain polyamide materials including recurring units comprised, for example, of inter-bonded aromatic rings where the aromatic rings are in twisted relation to one another, it where the aromatic rings are in a non-coplanar molecular configuration with respect to each other or, preferably, in mutually orthogonal planes. It has been found that the presence of substituent moieties on inter bonded aromatic radicals, of type and position such as to effect a non-coplanar molecular configuration with respect to the inter bonded aromatic radicals, provides a recurring unit having a high geometric index. The condition of non-coplanarity among aromatic rings in a recurring unit, or presence in such units of rings in "twisted" configuration relative to one another has been found to be importantly related to high birefringence in the rigid rod-like oriented polymers resulting grow the end-to-end joining of such recurring units.
Among polyamide materials suited to application as highly birefringent layers in the devices of the invention are polyamides comprising repeating units of the formula JO O R

to - A C - N - BUN
wherein each of A and B is a diva lent radical, except that B
can additionally represent a single bond; R and Al are each hydrogen, alkyd (e.g., methyl, ethyl), aureole (e.g., phenol, naphth~yl), alkaryl (e.g., toll), aralkyl (ego bouncily); c is zero or one; and wherein, when c is one, at least one of A and B is a diva lent radical selected from the group consisting of:
(1) a diva lent substituted biphenyl radical We Or where U is a substituent other than hydrogen, each W is hydrogen or a substituent other than hydrogen, p is an integer from 1 to 3, each X is hydrogen or a substituent other than hydrogen and r is an integer from 1 to 4, said U, We and Or substitution being sufficient to provide said radical with a non-cop1anar molecular configuration; and (it a diva lent substituted stilbene radical I

where each of Y and 7, is hydrogen or a substituent other than hydrogen and each t is an integer from 1 to 4, with the proviso that when each said Z is hydrogen, at least one said Y substituent is a substituent other than hydrogen positioned on the corresponding nucleus o'er with respect Z
to the -C= moiety of said radical, said and Ye substitution being sufficient to provide said radical with a non-coplanar molecular configuration;
and wherein, when c is zero, A is a diva lent radical selected from the group consisting of radicals (1) and (~) as herein-before defined.
As used herein, substitution sufficient to provide a radical with a non-coplanar molecular configuration refers to substitution of type and position effective to confer to the inter bonded aromatic radical thereof a non-coplanar molecular configuration such that the value of the geometric-index, as herein before defined, is about 0.5 or higher. Preferably, the nature of such substitution will be sufficient to provide a G
0 value of 1.0 or higher, and most preferably, 1.2 or higher.
As described herein before, birefringent polyamides useful in devices of the present invention include those come prosing recurring units of the formula I
t C - A C - N - No ho wherein c is zero or one and wherein A (when c is zero) or at least one of A and B (when c is one) comprises a substituted diva lent biphenyl radical or a subset-tuned diva lent stilbene radical. Thus, when c is zero,divalent radical A comprises a substituted biphenylene radical having a non-coplanar molecular configuration or a substituted ... ... . . .

diva Len stilbene radical of non coplanar molecular configuration.
Similarly, when c is the integer one, one or both of diva lent radicals A and B comprises such substituted biphenylene or substituted stilbene radicals. It is preferred from the stand-S point of ease of preparation that each of R and Al be hydrogen, although each of R and Al can be alkyd, axle, alkaryl or aralkyl.
From inspection of the general formula set forth as descriptive of recurring units of the polyamides of Formula I, it will be appreciated that polyamides comprising the following recurring units are contemplated when c is one:

-E Al C - A - C - N - B - N Formula II
In such recurring units, at least one of divinity radicals A and B will comprise a substituted biphenylene or substituted ... . ; _,_ stilbene radical of non coplanar secular configuration conforming to the formulae ; Formula III
We Or or C-C formula IV
.. . . .. .. . . ...... .. . . .
Where only one of said A and B radicals is a substituted biphenylene ox substituted stilbene radical conforming to the radicals represented by the structures of Formulas III
and IV, toe remaining A or B radical can comprise any of a art of delineate radicals so long as the birefringent properties of the polyamide material are not effectively us negated. In general, where only one of the A and B radicals conforms to the structures represented by Formulas III and IV, the remaining A or B radical will desirably be a delineate radical which does not confer transverse eccentricity to the recurring unit. Similarly, where one of radicals A or B is a radical which confers transverse eccentricity to the recurring unit, the other of radical A or B will desirably be a radical which confers high longitudinal eccentricity such that the recurring unit of the polymer exhibits a high geometric index. Suitable diva lent radicals include for example, unsubstituted biphenylene or s~ilbene radicals;
phenylene; trans-vinylene; or ethynylene. Also suitable are polyunsaturated diva lent radicals conforming to the formula Elm c = CJ

where n is an integer of at least two (e.g., two or three) and each of D and E is hydrogen or alkyd (e.g., methyl) and inkwell-size of such polyunsaturated diva lent radicals as transitoriness-1~1 }l 1,4-butadienylene, i.e., -C-C-C=C- ; and 1,4-dimethyl-trans-H H
SHEA H
trans-1,4-butadienylene, i.e., -C - C - C = C- . It will be SHEA
appreciated that compounds containing amino groups directly attached to carbon atoms having linear unsaturate radicals are not stable and that, accordingly, the aforesaid vinylene, ethynylene and butadienylene radicals cannot serve as B radicals in the recurring units represented by the structure of Formula II.
In general, from the standpoint of maximized biro-fringent properties, it will be preferred that each of radicals A and B comprise a diva lent radical exhibiting a non-coplanar molecular configuration and conforming to the structures of Formulas III or IV. It will be appreciated, however, that the I

particular nature of such A and B radicals may affect the ability to readily orient the polyamide material, as by extrusion, stretching or the like. Accordingly, where the ability of a polyamide material to be oriented is effectively reduced by the presence in the polyamide of each of radicals A and B of non-coplanar molecular configuration and conforming to the structures of Formulas III or IV, it will be preferred that only one of such radicals A and B of the polyamide material conform to the structure of Formulas III or IV.
In the case of radicals A and/or B of the recurring type represented by Formula ILL, U will comprise a substituent other than hydrogen; W will be either hydrogen or a substituent other than hydrogen; and p will be an integer ox from 1 to 3.
In the case of such radicals, X will be hydrogen or a subset-tent other than hydrogen and r will be an integer of from . 1 to 4. It will be appreciated from the nature of U, I, p, X and r, as set forth, that at least one aromatic nucleus of the biphenylene radical represented by Formula III will be substituted by a moiety other than hydrogen and that such O substituent, U, will be positioned in an ortho relationship to the bridging carbon atoms of the biphenylene nuclei.
Preferably, each aromatic nucleus of the biphenylene radical of Formula III will contain a substituent other than hydrogen positioned in an ortho relationship to the bridging carbon '5 atoms of the biphenylene radical of Formula IT and in this case, the diva lent radical will haze the following formula . Formula V
Jo wherein each of and X comprises a substitutent other than hydrogen.

The nature and positioning of substituents U, and X of the biphenylene radical of Formula III can vary widely, consistent with the provision of a biphenylene radical having a non-coplanar molecular configuration. While applicants do not wish to be bound by precise theory or mechanism in explanation of the highly birefringent character observed in oriented polymers comprising recurring units of high geometric index, it is believed that the non-coplanar character conferred or promoted by the presence in a polymer of such recurring units provides a distribution of high electron density cylindrically about the long axis of the polymer. This distribution is believed to be importantly related to unusually high birefringence observed in such polymers.
The nature of substance, U, We and Or should be such as to provide the biphenylene radical of formula III with a non-coplanar molecular configuration referred to herein before.
Such configuration will in part be determined by the positioning and size of non-hydrogen substituents on the aromatic nuclei of the biphenylene radical and upon the number of such subsfituents on such aromatic nuclei. For example, where the bi~,lenylene radical contains a single non-hydrogen substituent, i.e., substltuent U, the nature and, in particular the size of such U substituent, should be such as to provide the desired non-coplanar molecular configuration. Suitable U substituents herein include halogen (e.g., flyer, sheller, broom, idea);
vitro; alkyd (e.g., methyl, ethyl); alkoxy ego., methoxy);
substituted-alkyl (e.g., trifluoromethyl or hydroxymethyl);
cyan; hydroxy; thioalkyl (e.g., thiomethyl); car boxy;
sulfonic acid esters; sulinic acid esters; car boxy-I

aside; sulfonamide; amino; and carbonyl. Substituent X can comprise hydrogen or any of the substituents set forth in connection with substituent U. Preferably, at least one X sub-stituent will comprise a substituent other than hydrogen. Each substituent W can comprise hydrogen or a substituent other than hydrogen as set forth in connection with substituents U and X.
Normally, W will be hydrogen and p will be the integer 3.
Preferred polyamides herein are the polyamides come prosing recurring units having the biphenylene radical of lo Forr.lula V, ire., U
o Formula V

wherein each of U and X is a substituent other than hydrogen.
The presence of such non-hydrogen substituents on each of the aromatic nuclei of the radical promotes a condition of non-coplanarity. Examples of such preferred substituents, which may be the same or different, include halo, vitro, alkoxy and substituted-alkyl (e.g., trifluoromethyl). While the presence of such non-hydrogen substituents is preferred from the standpoint of promoting non-coplanarity, it will be appreciated from the nature of substituents W and X set forth in connection with Formula III herein before, that each X and W can be hydrogen and that, accordingly, substituent U will in such instance desirably comprise a bulky substituent such as will provide steno hindrance to a condition of coplanarity.
In the polyamides of the present invention which comprise recurring units represented by the following formula O C' R Roll Formula _ -C A - C - N - B - N I-either or both of radicals A and B can comprise the substituted stilbene radical set forth herein before as Formula IV, i.e., y Ye I Formula IV
~C~C

In such stilbene radicals, the nature of each Y and Z will be such as to provide the radical with a non-coplanar molecular configuration. Preferably, non-coplanarity will be provided by the presence of a single non-hydrogen substituent Z. Whole each Z is hydrogen, non-coplanarity can be provided by the positioning of a non hydrogen Y substituent on at least one aromatic nucleus of the radical in an ortho relationship to the -C= moiety of the radical. Suitable non-hydrogen Y and Z substituents include, for example, any of those set forth in connection with radicals U, W and X defined herein before.
Examples of preferred stilbene-type radicals included within the class represented by Formula IV include the following:

Y H

C- 1 Formula VI

where at least ogle of the Y substituents is other than hydrogen, preferably, halo or alkoxy; and H

C - C Formula VII

where Z is a substituent other than hydrogen, preferably halo.
Inclusive of polyamides of the present invention represented by the structure of Formula II ore those having recurring units represented by the following structures wherein, unless otherwise specified, U, W, p, X, r, Y and t have the meanings set forth herein before:

¦ - C N - Jo N ; PormulavlI

We Or We r ~17-pi t 30 I c I I Formula It We Or to con I Formula X

O H O H V H
_ CHIC = C~C - N No _; Formula XI

I
'' We Or , tic = I CON ONE Jo FormulaXIII

o 'X Z Z y O H Y Z Z Y H
= C CON C = 1{~>11 Formula XIV

I - C C - C = C - C - N I)_ N}; Fun via XV

_ . . .. . .. ..

-O Z H O H U H
C C = C C - N No Allah X

where Z and X are other than hydrogen; and Of U O H U Al 1 . I N J formula XVII
X X
where each X is other than hydrogen.
From inspection of the general formula set forth as descriptive of recurring UJlitS of the polyamides, i.e., recurring units of the formula I - A Formula I
it will be appreciated that, when c is zero, the recurring units will be represented by the following formula:
I
to - A - N Formula XVIII
In such recurring units, radical A will comprise a diva lent radical having a non-coplanar molecular configuration and conforming to the structures of Formulize and IV set forth herein before, i.e., U ., Formula III

We Or or C=C Formula IV

where U, W, p, X, x, Y, t and Z have the same meanings.
Inclusive of polyamides represented by the structure of formula XVIII are those having recurring units represented by the following structures wherein U, We p, X, r, Y and t, unless otherwise indicated, have the meanings set forth herein before:

C + ; ormolu XIX

C W : Formula XX

where X is other than hydrogen;
lo t I C = C I ; Formul a XXI

O Z H H
_ I C = I N - , Formula where Z is other than hydrogen While the polyamides described herein consist essentially of recurring units represented by the .5 structures of Formulas Rand XVIII, i.e., recurring units of the formulas r 11 8 1 Irk I Toll t I t a combination of such recurring units, the polyamides can .

also comprise recurring units not conforming to the described structures of Formulas IIand XVlII. Examples of recurring units which do not conform to such descriptions and which can be present in such polyamides in proportions which do not negate the high birefringence of the polymeric material include, for example, recurring units having the formulas O o If 11 -C - G - C- , Formula XXIII

R R

-N - G - N- , or Formula XXIV

R

C - G - N- Formula XXV

wherein G is a diva lent radical such as 1,4-phenylene;

4,4'-biphenylene; vinylene; trans,trans-1,4-butadienylene;

4,4'-stilbene; ethynylene; 1,5-naphthalene; 1,4-dimethyl-transrtrans-l~4-butadienylene; 2,4'-trans-vinylenephenylene;

trans,t~-4,4'-bicyelohexylene; 2,S,7-bicyclooctatriene-1,4-, i.e., I< ; or Jo , Other diva lent radicals can, however, serve as radical G
provided that such radicals do not adversely and materially reduce the birefringence of the polyamide material. It will be appreciated that G cannot represent an aliphatie unsaturated moiety where a carbon atom thereof having such unsaturation is to be bonded to an amino group.
The substituted polyamides utilized in devices ox the present invention can be prepared by resort to polyamide synthesis routes involving the polymerization of suitable acid halide and amine monomers in an organic solvent which may contain a solubilizing agent Suckle as lithium chloride or chain-terminatillg agent where desired. Polyamides of the type represented by the structure of Formula I can be prepared, for example, by toe reaction of a dicarboxylic acid halide of the R R
formula Hal-C~A-C-Hal with a Damon of the formula H-N-B-N-H, where Hal represents halogen, such as sheller or broom and A
and B have the meanings herein before set forth, except that B cannot represent an aliphatic unsaturated moiety. The reaction can be conducted in an organic solvent such as N-methyl pyrrolidone (NIP), ~etramethylurea (MU) of a mixture thereof, and preferably, in the presence of a salt such as lithium chloride to assist in the solubilization of reactant monomers and maintenance of a fluid reaction mixture. The preparation of a polyamide of the proselyte invention can be illustrated by reference to the preparation of pull'-dibromo-4,4'-biphenylene)-trans-t~-bromo-p,p'stilbbone dicarboxamide, a preferred polyamide herein, in accordance with the following reaction scheme:

C1- C C-C--~ Cal + HEN ~12 LlCl By o By H By H
I C No N- n Polyamides containing recurring units having the .. rod I 1 structure represented by Formula XIII, i.e., t C - A - N
can be prepared, for example, by the polymerization of a p-amino-aroyl halide monomer in the form of a halide, I

arylsulfonate, alkylsulfonate, acid sulfonate, sulfate or other salt. This polymerization can be illustrated by reference to the preparation of poly(2,2'-dibromo-4,4'-biphenylene)carboxamide in accordance with the following reaction scheme showing the polymerization of the hydra-chloride salt of 2,2'-dibromo-4~amino-4'-chlorocarbonyl-biphenyl:
Of Ho C Of 3 NO f Hal By By n Substituted polyamides useful in optical devices of the present invention can be prepared by polymerization of correspondingly substituted monomers in a suitable organic no-action solvent. Such solvents include aside and urea solvents including N-methyl-pyrrolidone and N,N,N'N'-tetramethylurea.
Other suitable reaction solvent materials include N-methyl-piperidone 2; N,N~dimethylpropionamide; N-methylcaprolactam;
N,N-dimethylacetamide; hexamethylphosphoramide; and NUN
dimethylethylene urea. The polymerization can be conducted by dissolving the monomer or monomers to be polymerized in the reaction solvent and allowing the exothermic polymerization reaction Jo occur usually with the aid of ox vernal cooling. In general, the polymerization will be conducted initially at a temperature of from about -20C to about 15C, and preferably, in the range of from about -5C to about 5C. Thereafter, usually within about one half hour to one hour, the reaction will be heated with formation of a thickened polymeric mass of gel-like consistency. In general, the polymerization reaction will be conducted over a period of from about 1 to 24 hours, preferably about 3 to 18 hours.

_ _ . . .

While the monomer or monomers to be polymerized can be dissolved in a suitable aside or urea solvent and allowed to react with formation of the desired polymeric Material, a preferred reaction sequence where a Metro of ccpolymerizable monomers is utilized involves the preparation of a solution of a first monomer in the aside or urea solvent and the addition thereto of a second or other monomer or a solution thereof in a suitable organic solvent thrower, such as twitter-hydrofuran. External cooling of the resulting reaction mixture provides the desired polyamide material if. high molecular weight and minimizes the production of undesired side reactions or by-products.
The polyamide materials prepared as described can be recovered by combining the polymerization reaction mixture with a non-solvent for the polymer and separating the polymer, as by filtration. This can be effectively accomplished by blending the polymerization mixture with water and filtering the solid polyamide material. The polyamide can be washed with an organic solvent such as acetone or ether and dried, for example, in a vacuum oven.
Polyamide materials as described herein before and methods for their preparation a-e described in greater detail in United States Patent 4,384,107.

the transparent highly birefringent materials useful in the devices of the present invention have been set forth by reference to certain polyamides, represented by the structures of Formulas II and XVIII, it will be appreciated that transparent highly bir~fringent polymeric materials of other polyamide types, or of types or classes other than ,.,, I, polyamides, can likewise be utilized herein where the repeating units of such polymers have a substantially cylindrical duster button of electron density about the long axis or the polymer.
Particularly useful herein are transparent polyamide materials comprising recurring units corresponding to Formula I
hereof wherein c is zero or one, each of A and B is a diva lent radical, except that B can additional represent a single bond, and at least one of A and 3 is a s-~bstituted-quaterphenylene radical having the formula LO

1`1p Or W

wherein U, W, X, p and r have the meanings set worth herein and the U, We and Or substitution is sufficient to provide the radical with a non-coplanar molecular configuration.
The above substituted-quaterphenylene polyamides can be prepared, for example, by reaction of a suitably substituted quaterphenylene Damon and a dicarbo~ylic acid or halide. These polymers and their preparation are described in greater detail and are claimed in the Canadian patent application of ROY. Gaul Diana and P.S. Kalyanaraman, (Serial Jo. 397,277) filed of even O date herewith.
Transparent polymeric materials from classes other than polyamides and which can be utilized herein include, for example, polymers having thiazole, imidazole, oxazole and/or ester linkages. For example, polymeric materials comprising the follow-in thiazole-containing recurring units, where U, Wry X, and r have the meanings herein before ascribed, can be utilized herein:

i 3 Us - -Such polymeric materials can be prepared by reaction of a dicarboxylic acid compound of the formula ICKY Ox C-OH

We Or with an ami~o-thiol of the formula

2 ~y,~~y,SH
s 101 in a suitable organic solvent with recovery of the desired polymeric material.
, Polymers comprising the following imidazole-containing repeating units can also be employed herein, where U, W, X, p and r have the meanings herein before described.

WOW
p r H

These polymers can be prepared, for example, by reaction of a dicarboxylic acid compound of the formula o U o OKAY C-OH

We Or , . . ... . .
with 1,2,4,5-tetramino-hen~ene.
Polymers containing recurring units having an oxazole moiety can be suitably prepared by reaction of a dicarboxylic acid compound as aforedescribed with, for example, 1,4-dihydroxy-2,5-diamino-ben2ene, with formation of a polymer containing the following recurring units where U, W, X, p and r have the meaning set forth hexeinb~fore.

I, I) ' N O J
We.. Or Polyester materials kennels be suitably employed herein. Exemplary of such polyesters are those having recurring units of the formula I I

We Or We Or wherein each U, W, X, p and r has the meaning set forth herein before.
Other polymers that can be utilized in optical devices of the present invention are polymers comprising JO recurring units of the formula r r Mu-C-Az-C

where Mu is a diva lent radical having the formula --Cluck - .
D' I' .
where each of D, D', E and E' is hydrogen, alkyd or .5 substituted-alkyl; and A is a diva lent radical having the formula R 1' -N-W-N-where each of R and R' is hydrogen, alkyd, aureole, alkaryl or aralkyl and W is a single bond, alkaline or alkenylene; or I A is a diva lent radical having the formula yo-yo -N N-where each of Y and Y' represent the atoms necessary to complete with the nitrogen atoms to which they are bonded a piperazine or substituted-piperazine radical.
These polymers can be conveniently prepared by reaction of a dunk acid chlorite such as mucononic acid chloride or dimethylmuconic acid chloride with hydrazine or a Damon such as piperazine, 2-methylpiperazine or 2,5-dimethylpiperazine. Suitable polymers of this type and methods for their preparation are described in United States patent 4,393,196.

The polymeric materials utilized in the devices of the present invention can be variously formed or shaped into films, sheets, coatings, layers, fibrils, fibers or the like.
For example, a solution of a substituted polyamide as described herein before, in a solvent material such as N,~-dimethyl-acetamide, optionally containing lithium chloride solubilizing agent, can be readily cast onto a suitable support material for the formation of a polymeric film or layer of the polyamide material. The polymeric film can be utilized for the product lion of a birefringent polymeric film or sheet material which can be utilized in an optical device of the invention. Thus, I a polymeric film or sheet material can be subjected to stretching so as to introduce molecular orientation and pro-vise a film material having a highly .~irefrir.~ent character.

I

., j.

Known shaping or forming methods can be utilized for the orientation of polymeric materials suited to application in devices of the present invention. Preferably, this will he accomplished by unidirectional stretching of a polymeric film, by extrusion of the polymer into a sheet, layer or other stretched form, or by the combined effects of extrusion and stretching. In their oriented state, the polymers utilized herein exhibit unusually high birefringence. To general, treater birefringence will be observed in the case of polyp metric materials exhibiting a greater degree of molecular orientation. It will be appreciated, however, as has been pointed out herein before, that the particular molecular struck lure or configuration of the polymeric material may affect desired physical attributes of the polymer material or other-wise impose a practical limitation upon the degree of oriental lion that can be realized by stretching or other means. It is a significant aspect of the present invention, however, that the polymeric birefringent materials utilized in the devices of the present invention, particularly for a riven degree of . orientation, exhibit unusually high birefrin~ence. In this connection, it is to be noted, for example, that the substituted polyamides described herein will often exhibit higher biro-fringence than the more highly oriented materials of different -limerick structure. For example, an extruded film of a tub-stituted polyamide hereof comprised of recurring units of the formula C = I C - N N

By and having a degree of orientation in the range of from about 80% to 85% as determined from infrared dichroism, exhibited a birefringence ( no of 0.865 as measured utilizing principles of interferometry. In contrast, a polyamide fiber material and comprised of recurring units of the formula:
o O H H
_ I C -- N N

is reported in the literature, ALA. Humus and J. Sikorsky, J.
Microscopy, 113, 15 (1978), as having a birefringence of 0.761, as measured by interferometric technique and at a degree of orientation of about 90% to 95%.
The birefringent polymers useful in the devices hereof will desirably simulate to the maximum practical extent the optical properties of a uniaxial crystal.
Accordingly, the birefringent polymers will exhibit substantially uniaxial optical behavior, i.e., only two indices of refraction. Optical efficiency and maximum birefringence will be realized where such substantially uniaxial behavior is exhibited by such polymers.
The molecularly oriented birefringent polymers utilized herein will preferably exhibit a birefringence of at least about 0.2, and more desirably, a birefringence of at least 0.4. Thus preferred polymers for use in the articles hereof will exhibit substantially uniaxial optical behavior and a birefringence of at least about 0.2 and will be comprised or recurring units naming a geometric index of about': 0.5 or higher.

_ = " = . = = ", .

The birefringent polymeric materials utilized in the devices of the present invention, in addition to exhibiting high birefringent properties, are advantageous from the stand-point of their transparency. In contrast to polymeric materials which become decidedly opaque as a result of stretching, birefringent materials hereof exhibit transparency in unwarranted end stretched forms. For example, the substituted polyamides described herein exhibit a high transparency and a low order of light scattering, exhibiting a ratio of amorphous to crystal-line material of from about 10:1 to about 20:1 by weight.
These materials are, thus, suited to optical applications where a light-transmissive, highly refractive and bireringent material is desirably utilized. Depending upon the nature of substituent moieties on the diva lent radicals of the recurring units of these polyamides, colorless or nearly colorless polyp metric films or layers can be fabricated. Inhere, for example, nitro-substituted biphenylene radicals are present, a yellow transparent film or giber can be fabricated. Films, coated or other shaped forms of the substituted polyamides can be redissolved end reshaped or prefabricated it desired. Depending upon the nature of particular recurring units of the polyamide materials, and particularly the nature of substituent moieties and solvent materials, the volubility characteristics of these substituted polyamides can be varied or controlled to suit particular applications.
The birefringent properties of polymers utilized in lo the devices of the present invention can ye determined by the measurement of physical and optical parameters in accordance with known principles of physics and optics. Thus, for example, the birefringence L n) of a suitable birefringent polymeric material can be determined by the measurement of optical phase retardation (R) and film thickness (d) and calculation of birefringence in accordance with the relationship R
d where represents the wavelength of light utilized for the conduct of the measurements. Alternatively, parallel refractive index and perpendicular refractive index of the film material can be measured utilizing Beck line analysis or critical angle measurement.
A preferred method for determining the birefringence of useful polymeric materials involves the measurement of retardation of the polymeric material by a method utilizing principles of polarized-light microscopy and interferometry.
Such method provides desired precision and accuracy in the measurement of the phase difference between a sample ray passing mu through a sample of polymeric material and a reference ray . _ ,,~

passing through a neighboring empty aria (embedding medium or air) of the same thickness The light emitted by a low-voltacle lamp of a microscope is linearly polarized by passage through a polarizer and, in turn, is passed through a condenser, a calcite plate beam splitter, a half-wave retarder plate, the polymeric sample, a beam recombinator calcite plate, and through an analyzer whose transmission direction is vertical to that of the polarizer (crossed position). In the analyzer the components vibrating in its absorption direction are ox-tinguished, whereas the components of both rays in the trays-mission direction are transmitted and interfere. The phase difference between sample and reference beams, caused by the molecular structure or configuration of the polymeric sample, is measured with compensators. From these measurements, the thickness and refractive index of the polymeric material can be determined. By determining index of refraction of the polymeric sample for both parallel and perpendicular directions, birefringence can, by difference, be determined. A suitable method and apparatus for determining phase retardation, index of refraction and birefringeance for the polymeric materials utilized herein is a pol-interference device according to Jamin-Lebedeff described in greater detail by WAGE. Patzelt, "Polarized-light Microscopy," Ernest Lutz GmbH, Wetzlar, West Germany, 1974, page 92.
Preferred optical devices of the present invention are multi layer devices which include a layer of molecularly oriented and highly birefringent polymeric material as described herein before, and in addition, at lest one layer of isotropic or birefringent material. The additional layer or layers.
I whether isotropic or bire~ringent, comprises a material having an index of refraction matching substantially one index of refraction of the highly birefringent material. For example, a layer of isotropic material having an index of refraction matching substantially one index of refraction of the highly birefringent layer can be suitably bonded to the layer of highly birefringent polymer. A preferred device comprises a layer of the molecularly oriented and highly birefringent material bonded between two layers of isotropic material, the index of refraction of each isotropic layer corset-lo tuning substantially a match with an index of refraction of the molecularly oriented and highly birefringent material.
Such a preferred device can be utilized for the pullers lion of light and may be termed a "total transmission light polarizer, i.e., one which is particularly adapted to polarize a very large portion of incident light. Total polarizers find application in equipment such as may be employed fox signaling, projection and display purposes, or the like, and in anti-glare systems for automotive vehicles.
2Q According to another embodiment of the present invention, a molecularly oriented and highly birefringent material as defined herein can be suitably bonded to an addition-at layer of birefringent material. In such an embodiment, one index of refraction of the molecularly oriented and highly birefrir.gent material will match substantially one index of refraction of the additional birefringent material. Similarly, the second index of refraction of the molecularly oriented and highly birefringent material will be substantially a mismatch with respect to the second index of refraction of the additional pa by no morel Where a layer of molecularly oriented and highly birefringent material is bonded to an additional layer of birefringent material, the direction of oriental on of each contiguous birefring~r.t material will be substantially perpendicular with respect to the other.
According to another embodiment of the present invention, a plurality of alternating isotropic and birefrin-gent layers can be utilized for the production of a multi layer light polarizing device, at least one of the layers of birefringent material comprising a molecularly oriented and highly birefringent material as defined herein. Such a device can be utilized as a multi layer polarizer which partly transmits and partly reflects incident light as separate linearly polarized components vibrating in orthogonal directions.
In Fig. 5 is shown, in considerably exaggerated dimensions an optical device of the present invention in the form of light-polarizing sheet material 10 as it would appear in cross-section, namely, as viewed axons a given edge.
In order of arrangement with respect to the direction of a collimated beam 12 from a light source (not shown) the material is composed of an isotropic, or at least functionally isotropic layer 14 having a relatively low refractive index, a molecularly oriented highly birefringent polymeric layer 16 and a functionally is~txopic layer 18 having a relatively high refractive index, the layers preferably being laminated or bonded together to form a unitary structure. It is not essential to the proper functioning of the device that the layers thereof be bonded together; provided, however, that adjacent or contiguous layers enclosing an air layer are maintained parallel to one another One refractive index of the polymeric molecularly oriented and highly birefringent - -layer 16 matches substantially that of layer 14 while the other refractive index thereof matches substantially the index of retraction of Mayer 18. For purposes of illustration, the alone-said refractive indices may be liken as follows: the refractive index of layer 14 is 1.50; the two indices of layer 16 are 2.00 and 1.50; and the index of layer 18 is 2.00.
The interface between layers 14 and 16 is composed of a plurality of lens-like or lenticular elements aye and the interface between layers 16 and 18 is composed of a plurality of lens-like or lenticular elements 16b. It will be noted that Lye lenticules of one interface are offset, laterally, with respect to those of the other. The term "lenticular", as employed herein, may broadly be interpreted as constituting a plurality of surface configurations, including prismatic elements, as well as those of a strictly lens-like form. A
certain degree of latitude is possible as to the choice of materials employed in forming the several layers. Thus, for example, layer 14 may suitable be composed of an isotropic plastic material such as poly~methylmeth~crylate) having a refractive index of 1.50. Layer 16 can, accordingly, be come posed of a transparent plastic layer which, for example, has been rendered birefringent as by unidirectional stretching.
Suitable for this purpose is the polymeric material, pull'-bis(trifluoromethyl)-4,4l-biphenylene]2",2"'-dimetthwacks"'-biphenyldicarboxamide having refractive indices of 1.50 and 2.00 when thus rendered birefringent. Layer 18 can be suitably comprised of or incorporate a transparent isotropic material having an index of refraction approximating the higher index of birefringent layer 16.

. .

One such material is poly(2,2'-dibromo-4,4' biphenylene)-4,"4"'-stilbenedicarboxamide having an index of refraction of 2.07. Alternatively, layer 18 can comprise poly(2,2'-dibromo-4,4'-biphenylene)-~-bromo-4",4"''-stilbene-dicarboxamide having a refractive index of 2.05.
One method of constructing the sheet material is to form the birefringent layer 16 by a casting, or a casting and embossing procedure, after its proper solidification, and casting the isotropic layers 14 and 18 on the opposite lunatic-far surfaces thereof. The birefringent layer I may be composed of substantially any material having a birefringence adapted to facilitate the required separation of light ray components and having indices of refraction which bear a proper relation to those of the contiguous layers 14 and 18. It may also be formed by any of several different procedures. Assuming, by way of illustration, that the birefringence of layer 16 is to be achieved to ought its molecular orientation, a sheet or film of properly deformable material, such as the aforementioned material, poly[2,2'-bis(trifluoromethyl)-4,~'-biphenylene]-2",2"' -dimethoxy-4",4" -biphenyldicarboxamide, i.e., a sheet of a given length and predetermined thickness, can be first extruded or cast. The sheet can then be subjected to a mechanic eel stress in a longitudinal direction to elongate and Milwaukee-laxly orient it, as by a stretching operation in the presence of heat or other so toning agent, or by a cold drawing method, or, again, by applying a mechanical stress to its surface.
The direction of stretch or other application of orienting stress is to be taken as having been performed toward and away from the viewer, namely, in a direction normal to the plower of the awry; is being the case, the optic axis 20 of layer 16 constitutes a direction both in the plane of layer 16 and normal to the plane of the paper.
Birefringent layer Lo, having acquired the desired birefringence 25, for example, a birefringence of 1.50 and 2.00, assuming the stated refractive indices, can then be subjected to surface modification to form thereon the converging or positive lenticular elements aye and the diverging but functionally converging or positive lenticular elements 16b.
This can be suitably performed by passing the material between embossing means such as embossing blades, wheels or the like, the surfaces being slightly softened as by a solvent or heat, or both, as may be necessary during their treatment but not to such an extent as would relax the material and alter the previously provided orientation and birefringence.
The embossing procedure is preferably performed in a direction along that of the optic axis, to facilitate preservation of the given orientation. Accordingly, the lenticules, as illustrated, are generally cylindrical with their axes extending parallel to the optic axis. As will be apparent and explained in further detail below, the lenticules play a major role in the predetermined separation and focusing of the respective rays. While len~icular means of the type described constitute one preferred configuration, they may be so formed as to extend in other directions of the sheet or even have a spherical shape, provided that their refractive characteristics are properly chosen and the birefringence of the material is suitable. Alternatively, the lenticules may be formed by a grinding and polishing procedure or the sheet may be stretched or otherwise treated for orienting its molecules after the lenticules have been formed thereon.
After completion of the surfacing of the birefrinqent 'ever 16 and either prior to or after its orientation, the isotropic layers 14 and 18 are assembled therewith or formed - 5 thereon by any appropriate method such as by casting them in liquid form on the preformed layer 16. Assuming that the material of layers 14 and 18 is not of a type to cause any disturbing double refraction of light rays when solidified and subjected to mechanical stress, as by stretching, the stretching and desired molecular orientation of layer 16 may be accomplished after casting and solidifying layers 14 and 18 on it surfaces, the entire sheet 10 then being stretched as a unit. Or, the layers 14 and 18 may be cast on layer 16 after orientation of the latter. Alternatively, and again assuming layers 14 and 18 to be substantially incapable of becoming birefringent when stressed, they may be preformed so as to have the lenticular surfaces shown, superimposed in correctly spaced relation, the birefringent layer 16 formed there between in a fluid state and solidified, and the entire unit then stretched. In a further modification, the layers 14 and 18 may be preformed and assembled with layer 16, in either a bonded or non-bonded relation therewith, after the layer 16 has been treated to acquire a proper birefringence.
It has been noted with reference to Fig. 5, that the lenticules aye and 16b are relatively offset from left to right, that is transversely of the sheet 10, so that the Yen-tires of lenticules aye are optically aligned with the longitudinal edges or intersections of lenticules 16b.
While the lenticules aye and 16b are shown as being spherical and of similar radii ox curvature it will be understood that -39- .

neither of these conditions is essential, per so, the choice depending in general upon the directions in which the rays are required -to be refracted, the extent of their travel in said directions, and such factors as the refractive indices and thicknesses of the layers.
The collimated beams 12, emanating, for example, from a light source and reflector of a headlamp (not shown) - and normally incident upon the isotropic layer 14, are transmitted without deviation through the latter to the converging cylindrical lenticules aye of birefringent layer 16.
At layer 16 each beam is resolved into two components, that is an ordinary or "O" ray aye and an extraordinary or "E"
ray lob. Bearing in mind that the refractive index of isotropic layer 14 has been given as 1.50 and the refractive indices of birefringent layer 16 as 1.50 and 2.00 let it be assumed that the 1.50 refractive index applies to the components aye which, or purposes of illustration, Jill be considered the ordinary jays vibrating substantially at right angles to the optic axis. Inasmuch as these rays have a refractive index which is essentially identical to that of layer 14, which precedes layer 16 in order of their travel, they are refracted by lenticules 16b so to converge generally toward a theoretical focal plane, not shown. The rays aye pass through isotropic layer 14 without deviation inasmuch as the refractive index of 1.50 and that of layer I are substantially identical. The components lob, which in this instance are taken as the extraordinary rays vibrating in a plane passing through or parallel with the optic axis and having a refractive index ox: 2.00 identical to that of the isotropic layer 18, are I refracted by the lenticule!3 aye because of the dissimilarity of I

respective refractive indices. However, the diverging or negative lenticular surface aye constitutes, in effect a con-verging lenticular surface of isotropic layer 14, the components i2b thereby being refracted convergently toward the aforesaid theoretical focal plane. As described, the layer 16 is positively birefringent inasmuch as the refractive index ox the E ray is represented as greater than that of the O ray, but a reverse condition is possible. The rays aye and 12b, generated in birefringent layer 16 are plane polarized, their vibration directions being at 90 to one another as indicated.
The rays are thence transmitted WitilOUt alteration of their state of polarization with their vibrational planes normal to one another.
Either the E or the O ray, or both, may be selectively treated, as by passing them through retardation materials, to provide their vibrations in a single azimuth as will be described below. Even without such treatment and a non-uniformity of vibration directions, the sheet material of Fig. 5 has certain uses such, for example, as for illumination purposes where it is desired to polarize the light partially in a Yin direction, for three-dimensional viewing or for any function wherein transmission of a large part of the incident light is of importance but wherein completely uniform polarize-lion throughout a given area is not essential. While the entering rays 12 are shown us collimated at 90 to the plane of the sheet, a slight departure from this condition, from left-to-right in the drawing, can exist without preventing operation of the device of Fig. 5 or of others illustrated herein and a wide deviation therefrom may exist in a direction along the axis of the lenticules.

Consistent with obtaining an operational refraction or non-refraction of rays generally similar to that shown in Fig. 5, the several layers may be formed of substantially any materials having suitable refractive in cues, transparency and physical or mechanical properties such as thermal stability, flexibility or adhesion. Thus, for example, layer 14 may be composed of any of such materials as twitter-fluoroethylene, vinyl acetate, cellulose acetate bitterroot, an acrylic material, glass or the like. Birefringent layer 16 can be, for example, poly[2,2'-bis(trifluoromethyl~-4,4'-bip~.enylene~4",4"' -stilbenedicarboxamide having indices of refraction 1.61 and aye or a layer of poly(2,2'-dlbromo-4,4'-biphenylene~-4"/4"' -stilbenedicarboxamide having indices of 1.77 and 2.64. Layer 18 can be a polymeric material which has been rendered birefringent but which has its optic axis or direction of molecular orientation at 90 to that of layer 16, it being understood that its len~icular surface Gould match with that of layer 16 at 16b.
In an optical device of the present invention, the indices of refraction of the several layers can be modified or adjusted in predetermined manner such that the proper functional relation between the indices of refraction of the several layers is maintained. Thus, the indices of refract lion of the several layers may be controlled in predetermined fashion by altering plasticizer content. For example, the index may key lowered by the addition of plasticizer. Where bonding substances or subgoals are employed in laminating preformed layers, a material used for such a purpose Shelley have an index of refraction similclr to that of one of the . _ _ _ . _ . _ . . , .. . .. , _ . .. .. . ... . . _ . _ .

layers undergoing bonding to prevent unwanted reflection.
According to another embodiment of the present invention there is provided a light-polarizing element comprising a prismatic layer of molecularly oriented biro-fringent material and an isotropic or functionally isotropic layer. Such an element can be utilized in a device such as the headlamp of an automotive vehicle.
In Fig. 6 there is shown a headlamp 30 which includes a specularly reflecting parabolic mirror 32, a filament 34, a diffusely reflecting plate element 36 and a light-polarizing sheet material 40. Light-polarizing element 40 includes a prismatic layer 42 of molecularly oriented and highly birefringent polymer and an isotropic layer 44, the refractive index of the isotropic layer a substantially matching the low index of refraction of birefringent layer 42.
Thus, for example, birefringent layer 42 may have refractive indices of 2.0~ and 1.50 and layer 44 a refractive index of 1.50. An unpolarized collimated beam 12, upon entering birefringent layer 42, is resolved into O and E components aye and 12b, as previously described in connection with the device shown in Fig. 5. The prism elements of biro-fringent layer 42 are so formed and disposed relative to the incident collimated beam 12 that the E ray 12b is no floated rearwardly to the parabolic mirror 32, is reflected to diffusely reflecting element 36, whereat it is Doppler-Zen, is reflected to mirror 32 and thence to light-polarizing sheet material 40 as a second collimated unpolarized beam 12d. The prism elements, may, for this purpose, appear-privately be prisms or so-called hollow corner cubes which have the characteristic of reflecting collimated light rays in the direction whence they came. The O ray aye is transmitted without deviation straight through layer 44 which matches its refractive index. Thus procedure repeats itself, ad infinitum, it being apparent that eventually substantially all of -the light from source 34 is transmitted in the form of collimated O rays having a uniform azimuth of polarization.
According to still another embodiment of the present invention, there is provided a multi layer light-polarizing device effective to linearly polarize a large portion of the light incident thereon and to transit substantially all of one polarized component of light while reflecting substantially all of the orthogonally polarized component. Such a polarizer is shown in Fig. 7 as polarizer 50 having alternate layers 54 and 56 of molecularly-oriented, highly-birefringent material and of isotropic or functionally isotropic material.
The layers 54 are each composed of a molecularly oriented birefringent materiel. For instance, the material may comprise poly~2,2'-bis(trifluoromethyl)-4,4'-biphenylene]
2",2"' -dimethoxy-4",4"'-biphenyldicarboxamide. Other materials can also be utilized in forming the birefringent layer and should be selected to have as great a difference between the two indices of refraction as possible since the number ox layers in the polarizer can be substantially decreased when using bi,-efringent materials having a greater difference between their indices of refraction.

I

The isotropic layers 56 may be composed of a number of different materiels with the requirement that its refractive index substantially match one of the refractive indices of the birefringent material layers on either side thereof. Some examples of materials which are useful for this purpose include polyacrylates, poly(2,2'-dibrGmo-4,4'-biphenylene)4",4"' -stilhenedicarboxamide, silicon oxides or titanium dioxides. The isotropic layers can be provided, for example, by vacuum deposition so that their thickness can be precisely controlled. Alternately, the isotropic layer may be co-extruded simultaneously with the birefringent layers interleaved there between.
As shown in Fig. 7 the optical axis 58 of each birefringent layer lies in a plane parallel to the planar substrate surface 60. This is accomplished, for example, through the use of a stretch orientation operation. Layer thickness can be suitably controlled by the extrusion process and allowances for dimensional changes expected in the layer thickness during the stretching step can be made.
Fig. 7 schematically shows a number of light rays 62 incident on polarizer 50 and traveling in a direction perpendicular to the surface thereof. As an example, the birefringent layers 54 may have a pelf of refractive indices of no = 1.50 and no = 2.00 and the refractive index of each isotropic layer may be taken as n = 1.50. As each ray 62 passes through the first bir~fringent layer 54, it is -resolved thereby into two components shown as separate rays, . I

namely/ an extraordinary or "E" ray aye for which the biro-fringent layer has the higher index no = 2 7 00 and an ordinary ray or "O" ray 62b for which the birefringent layer has, for example, the lower index JO = 1.50 , the rays traveling in a similar direction and with their vibration azimuths relatively orthogonally disposed as depicted in the drawing. As shown in jig. 7, a portion 62c of the "E"
rays aye is reflected at the first interface 64 -cached, it being recalled that the refractive index of an isotropic lyres given at n = 1.50 The reflection is due to the refractive index discontinuity at the interface between the layers 54 and 56 which exists for the "E" polarization but not the "O" polarization. For purposes of illustration the reflected light rays 62c are shown as being reflected at a slight angle while in actuality they are reflected straight back it the direction of rays aye. Thereafter each inter- ¦
face such as 66 and 68 will reflect a further portion of ray aye. The rays 6~b are unreflected at the interface 64 because the refractive index for "O" rays 62b in layer 54 matches that of layer 56 and in fact, these rays 62b will pass through all layers 54 and 56 unreflected and comprise that portion of the light incident on the polarizer that is transmitted thereby.
In order to greatly increase the reflectivity of the polarizer 50 each layer 54 and 56 is made to have an optical thickness of one-quarter the length of a selected wavelength. The optical thickness is equal to the physical thickness multiplied by the index of refraction of the layer b material. The wavelength selected is preferably in the middle of the visible spectrum, for example, 550 no so that I

_ . . .. ... .

I

the polarizer is effective over a substantial range of visible light. This arrangemerlt utilizes optical inter-furriness to enhance the efficiency of the polarizer. The following discussion relates to phase changes in a light wave, not to changes in the the polarization azimuth of the light wave. In analyzing the optical properties of the polarizer, it is important to remember hat light suffers a phase change of on reflection when it goes from a medium of low refractive index to a medium of higher refractive index while it suffers no phase change on reflection when it goes from a medium of high refractive index to a medium with a lower refractive index. Thus, in Fig 7, a light ray such as aye, as it passes through the first quarter-wave birefringent layer 54 will suffer a phase change I
As the light ray strikes the first interface 64 part of it is reflected back through the first birefringent layer 54 again suffering a phase change of I the total phase change being equal of I + I If. Note that tune ray aye suffers no phase change on reflection at interface 64 due to the I rule as stated above. Now as the remaining portion of ray aye strikes the second interface 66, it has traveled through two layers suffering a phase change of I I
in one direction and I + I on reflection. The ray aye will also suffer a phase change of r on reflection due to the above rule and the total phase change will equal 4 I +
or 3 I. Thus, in accordance with this analysis, the ray aye will always suffer a phase change of some multiple of as it is reflected from each and every interface in the multi layer polarizer. Each reflected component 62c of ray aye and other such similar rays will reinforce one another resulting in substantially total reflection of the one polarized component of incident light represented by rays aye providing the number of layers and interfaces are sufficient. The other component 62b will pass undisturbed through the multi layer polarizer 50 so long as the refractive index of the isotropic layers 56 match one of the refractive indices of the birefringent layers 54. Since substantially none of the rays aye are transmitted, the entire amount of light output from polarizer 50 consists of rays 62b, ail polarized in one direction.
In Fig. 8 is shown on optical beam-splitter device of the present invention embodying a layer of birefringent polymer.
Beam splitter 70 comprises prisms aye and 72b of isotropic material]. such as glass joined in a Nikolai configuration with layer 74 of molecularly oriented birefringent polymer there-between. Elements aye and 72b can be composed of a variety of glass or other isotropic materials and will have a per pen-declare index of refraction greater than that of the polymer layer 74 between such elements. For example, a unidirection-ally stretched layer 74 of poly-[2,2'-bis(tri~luoromethyl~-4,4'~biphenylene]-~,2'-dimethoxy-4,4'-biphenyl having a per pen-declare index of refraction of about 1.65 and a unidirectional stretch direction as indicated in Fig. 8 can be utilized between isotropic glass elements aye and 72b of refractive index I In operation, unpolarized light 76 enters element aye and a portion thereof is reflected at the interface of element aye and layer 74 50 as to emerge as plane-polarized light 78. A portion of light 76 is refracted by layer 74 and emerges from element 72b as oppositely plane polarized Lotte 80.
Light 76 is thus split into separate beams of oppositely polarized light by beam splitter 70.

I

ilk particle cmbodilnc~ s of the prcscn~ invcn-lion utilizing polymeric birefrinyen~ layers have bean ; described in connection wit the devices Shelley in Fig 5 to 7, other devices utilizing such polymeric bircfrillgcnt layers can also be prepared. Examples of other devices which can be adapted to include a polymeric all highly birefringent layer as described herein are described, for example, in US. Patent 3,506,333 (issued April 14, 1970 to Eland;
in U. S. Patent 3,213,753 (issued October 26, 1565 to H. G. Rogers); in U. S. Patent 3,610,729 (issued Oc'obcr 5, 1971 to H. G. Rogers); in US. Patent 3,473,013 (issued October 14, 1969 to H. G. Rogers); in US. Patent 3,522,984 (issued August 4, 1970 to H.G.Rogers); in US. Patent 3,522,985 ; (issued August 4, 1970 to }I.G.Rogers); in Us Patent 3,528,723 (issued September 15, 1970 to H.G.Rogers); and in So Patent

3,582,424 (issued June 1, 1971 to K. Nervous). Still other devices that can be prepared utilizing a birefringent polymer hereof include Wallaston prisms, Russian prisms, Fuessner prisms, Brewster polarizers, non-polarizing beam splitters, compensators and the like.
The following non-limiting examples are illustrative of the present invention.

x7\~lp~
This cxarnplc illustrates the preparation of posy (2,2'-dibromo-fi t fi'-biphcnylclle)-p,p'-biphcnylene dicarboxaMidc and the preparation therc~om of birefringent polymeric films.
A 50-r~ll. Rockwell vessel (a resin-making cattle equipped Wltil a mechanical stirrer, nitrogen inlet tube and calcium chloride drying Tokyo) was heated while simultaneously flushing the Bessel wit nitrogen. After the reaction vessel had cooled to room temperature, 1.63 grams of an hydrous lithium chloride and 0.5746 gram ~0.00].679 mole) of sublimed 2,2'-dibromobenzidine were added while maintaining a positive I nitrogen pressure. The reaction vessel was fitted with a . .
thermometer and a rubber stipple (a rubber membrane e sealing lid capable of receiving a syringe and of sealing lo itself upon removal of the syringe). Ten mls. of an hydrous distilled N-methylpyrrolidone (NIP) and 15 mls. of an hydrous distilled ~e~=~methylurea (MU) were carefully added with the Jo aid ox syrinxes. The resulting mixture was stirred and warmed to 40C until all solids had dissolved. The solution was when cooled in a heath ox ice and salt to a temperature ! of -5C. A small amount of lithium chloride precipitation was obs~rvcd. Recrystallized p,p'-biphenylene dicarbonyl chloride (0.4689 gram; 0.001679 mole) was quickly added by means of a funnel to the stirred 2,2'-dibromobel-zidinc solution. on additional five mls. of MU were added through the funnel to the reaction mixture. The temperature of the reaction mixture did not rise above a temperature of 7C.
After stirring for 60 minutes, the reaction mixture bran to thicken and streaming birerringence (but not stir opalescence) was observed.

! The ice bath was removed from the reaction vessel Al 15 and the temperature was observed to rise to 20C in 30 minutes at which point the reaction solution became milky l in appearance. The reaction vessel was placed in an oil ; bath (40C) and the reaction mixture was warmed for 30 minutes. The reaction mixture became clear. The temperature of the reaction mixture rose during the warming to a maximum temperature of 55C at which temperature the reaction Metro was stirred for one hour. The reaction product, a 3% wt~/vol.
polymer solution (three grams of polymer per 100 mls. of reaction solvent) was cooled to ~0C and poured into 200 mls. of ice-water in a blender. The resulting fibrous solid was filtered and washed (in the blender) twice each with water, acetone and ether. The product was dried in a vacuum oven at lo mm.
pressure and 90C fur 18 hours the product, obtained in 95,4~ yield, was a white fibrous polymeric material having the following recurring structural units:

G C- N

~-51 .

The inherent viscosity of a polymer solution (0.5 gram of the polymer ox example 1 per 100 mist of a I solution of five yearns lithium chloride per 100 mls. of i dimethylacetamide)was 3.54 dl./yram at 30C.
¦ 5 Molecular structure was confirmed by infrared spectroscopy. Inspection ox the ultraviolet/visible absorption spectrum for the polymer of Example 1 (in So wt./vol. lithium chloride/dimethyl~cetamide showed a Max I
320(~ = 75,000).
Elemental analysis for Creole provided the following J I OH Brie ON I 0 Calculated: 56.97 2 92 29 16 ;.11 5 84 Fouled: 56.86 3 25 28 72 5.10 6 07 (my difference) lo Polymeric films were prepared from the polymeric material of Example 1 by casting (onto glass plat2s?solutions of the polymeric material in a 5% wt./vol. solution of lithium chlsxide and dimethylacetamide (five grams lithium chloride per 100 mls. of dimethylacetamide). The concentration of polymer ranged from OHS to I wt./vol., i.e., from 0~5 gram to five grams polymer per 100 mls. of the lithium chloride/
dLmethylacetamide solution. On each instance, toe glass plate carrying the puddle-cast polymer solution was immersed in water (after minimal evaporation of solvent). The polymer film was observed to gel and a transparent and colorless unwarranted film separated prom the glass plate. The resulting film was soaked for several hours in water to effe-:. extraction of occluded lithium chloride and solvent, soaked i!' acetone and dried in a vacuum oven at 90C and 15 em. pressure.
Retractive index, Mazda by inte~fe~ometry, was ii93 Jo S~xetchcd polymeric films were prepared in the followillg nlanller. Wa~er-swollell films (obtained by sicken the polymer films for several hours for removal of occluded hum chloride and solvent as aforedescribed) were cut into strips. The strips were mounted between the judges of a mechanic I eel unidirectional stretcher. The strips were stretched (in air at 220C) to about 50~ elongation, to effect film oriental lion. The resulting films were optically transparent. Biro-fringence, measured with the aid of a quartz wedge, was 0.293.
! lo EXAMPLE
'I
This example illustrates the preparation of posy (2,2'-dinitro-4,4'-biphenylene)-o,o'-dinitro-p,p'--biphenylene dicarboxamide and the preparation therefrom of birefringent polymeric films.
A 50-ml. reaction vessel pa rcsin-making kettle equipped with a mechanical stirrer, nitrogen inlet tube and calcium chloride drying tube) was heated while simultaneously Louisiana l-he vessel with nitrogen. Attacker the reaction vessel had cooled to room temperature, lo grams ox an hydrous lithium chloride and 0.47~9 swam (0.001750 mole) of recrystal-lived 2,2'-dinitrobenzidine yellow crystals were added while maintaining a positive nitrogen pressure. The reaction vessel was fluted with a thermometer and a rubber stipple and 30 mls.
of an hydrous distilled N-methylpyrrolidone (NIP) and 20 mls.
of an hydrous distilled tetramethylurea MU were carefully added with the aid of syringes. The resulting mixture was stirred and warmed to 40C until all solids had dis~olvcd. Lowe solution was then cooled in a bath of ice and salt Jo a temperature of -5C. Recrystallized colorless donator-

4,4'-biphenyl dicarbonyl chloride (0.6460 tram; 0.0')l75 Jo to) was quickly added by means of a funnel to the Seward I
dinitrobenzidine solution. An additional three mls. of No wore addocl Roy ho unloyal to the reaction mixer. The -tempcra~ure ox the reaction mlxtu~e did not rise above a temperature ox 0C. Altar stirring for 30 monks, there was no nuzzle change in reaction mixture viscosity.
The ice bath was removed-from the reaction vessel and the temperature was observed to rise to 20C in 30 minutes at which point the reaction solution was heated in stages up to 90C over a period ox 2.5 hours.
The reaction product, a OWE wt./vol. polymer solution (three trams ox polymer per 100 mls. of reaction solvent) was cooled o 40C and poured into 200 also of ice-water in a blender. The resulting gelatinous solid was filtered and washed (in the blender) twice each with water, acetone and ether. The product was dried in a vacuum oven at 15 mm.
pressure and 90C for 18 hours. The polymeric product, obtained in 88% yield, was a dark-yellow powder having the following recurring structural units:

-t C C No N -}_ The inherent viscosity of a polymer solution (0.5 grams of the polymer of Example 2 per 100 mls. of a soul-lion of five grams lithium chlorite per 100 mls. of dim ethyl-... .. . . . . .. , .,, . ....... . .. ..... . ......... . .
acetamide~ was 1.40 dl./gram at 30C.
Molecular structure was confirmed by infrared spectroscopy. Inspection of the ultraviolet/visible absorption spectrum for the polymer ox Example 2 (in I wt./vol. lithium chloride/dimethylacetamide) showed a Max of 30? no (I - 38,400) and an abrasion peak at 365 no = joy).
Elemental analysis for C26H14N6Olo p following:

3C lo Jo %0 Calcul~cd: 54.7~ 2.47 1~.73 28.06 ~~~~ 5~.24 2.60 13.~1 29.25 (by do furriness) Thermogravim~tric analysis showed that onset ox degradation of the polymer of Example 2 occurred at 360C in nitrogen and at 300C in air. Differential scanning calorimetry and thermal mechanical analysis of film samples showed a repro-educible transition at about 190C.
Polymeric films were prepared from the polymeric material of Example 2 by casting (onto glass plots solution of the polymeric material in a pow wt./vol. solution of hum chloride and dimethylacetamide (five Greece lithium chloride per 100 mls. ox dime~hylacetamide). The concentra-lion of polymer was I wt./vol., i.e., five grams polymer per lo lo mls. ox the lithium chloride/dimethylacetamide solution.
'In each instance, the glass plate carrying the puddle-cast polymer solution was immersed in water (after most of the solvent had evaporated). The polymer film was Observed to Mel and a transparent, yellow unwarranted film separated from the glass plate. The resulting film was soaked for several hours in water to effect extraction ox occluded lithium chloride and solvent.
Stretched polymeric films were prepared in the following manner. Water swollen films (obtained by soaking the polymer films for several hours for removal of occluded lithium chloride and solvent as aforedescribed) were cut into strips. The strips were marled between the jaws of a mechanical unidirectional stretches. The strips were stretched (in boiling ethylene glycol) to about 60~ elan-lion, to effect film orientation. The resulting polymer;

strips Whelk optically transparent Blrefrlngence, measured Whitehall tile aid of a quartz wedge, and by index Mekong, was 0~33. 'rho calculated isotropic refractive index was l.75.
Wide-angle Ray analysis ox the birefringent films showed crystalllnity to be less than lo by weight.

_ This example illustrates the preparation of posy (2,2'-dibromo-4,4'-b~phenylene)-o,o'-dibromo-p,p'--biphenylene dicarboxamide and the preparation therefrom of birefringent lo polymeric films.
50~ml. reaction vcss~l (a resin-makirlg kettle i keypad with a mechanical stirrer, nitrogen inlet tube and calcium chloride drying tube) was heated while simultaneously ; flushing the vessel with nitroscn. Afro the reaction vessel lo had cooled to room temperature, 2.0 grams of anhydrsus lithium chloride and 0.7828 gram (0.002289 mole) of sublimed 2,2'-dibromober~zidine were added while maintaining a positive nitrogen pressure. The reaction vessel was fitted with a thermometer and a rubber stipple and 20 mls. of an hydrous distilled N-methylpyrrolidone (NIP) no 35 mls. of an hydrous distilled tetramethylurea MU were carefully added w oh the aid of syringes. The resulting mixture was stirred and warmed to 40C until all solids had dissolved. The solution was then cooled in a bath of ice and salt to a temperature of 0C. Recrystallized 2,2'-dibromo-4,4'-biphenylene dicarbonyl chloride (1.0000 gram; 0.002289 mole) was quickly added by means of a funnel lo the stirred 2,2'-dibromobenzidine solution. An additional five mls. of rrMu~ at a temperature of 25C, were added through the funnel to the reaction mixture.
The temperature so the reaction mixture rose to 15C and wrier dropped to 4C. Tory stirring or 15 minutes, the wreck;
Myra Jan Jo thicken and streaming birefringcnce (buy no stir opalescence) was observed. Stirring was continued for an additional 30 monks at 7C and the ice bath was removed from the reaction vessel. The temperature ox the reaction mixture nose Jo 25C (in 90 minutes) and the reaction mixture was then slowly heated to 100C over a Tory period.
The reaction product, a 4% wt./vol. polymer solution (four grams of polymer per 100 mls of reaction solvent) was cooled to 40C end poured into 200 mls. of ice-water in a blclldcr. The resulting fibrous solid was filtered and washed (in the blender) twice each with water, acetone and ether. The product was dried in a vacuum oven at 15 mm.
pressure and 90C for 18 hours. The product, obtained in 96.6~ yield, was a white fibrous polymeric material having ! the following recurring structural units:

C C-N N

By the inherent viscosity of a polymer solution (OWE grams Go the polymer of Example 3 per 100 mls. or a soul-lion of five grams lithium chloride per 100 mls. of dim ethyl-~cetamide) was 2.04 dl./gram at 30C. Molecular weight determination based on light scattering, indicated 2.72 x 105, and by gel permeation chromatography, a molecular weight of

5.66 x 104. Molecular structure was confirmed by infrared spectroscopy. Inspection of the ultraviolet/visible absorption spectrum for the polymer of Example 3 (in I
wt./vol. lithium chloride/dimethylacctamide) showed a Max of 305 no ( , 31,900) and no absorption above 380 rum.

Y Bryan provided the ~ollowil~g:

-57~

.

I Lo if Yin JO
Calculated: 4~.23 1.'~9 45.27 3.99 ~.52 l = 4~.5~J 2.19 45.25 3D~7 4.15 by dif~crcllcc) it Thermogravimetric analysis showed that onset of Al 5 degradation of the polymer ox example 3 occurred at 530C in i nitrogen. Thermal mechallic21 analysis ox film samples showed a reproducible transition at about 120C.
Polymeric films ware prepared from the polymeric material of Example 3 by casting (onto glass plates) solutions of the polymeric material in a JO wt./vol. solution of lithium chloride and dime~hylacc~amidc (five grams lithium chloride per 100 mls. of dime~hylacetamide). The concentration 'i of polymer ranged from 0.5 Jo I wt./vol., i.e., from 0.5 gram to 5 grams polymer per 100 mls. ox the lithium chloride/
I, 15 dime~hylacetamlde solution. In each instance, the glass plate carrying the puddle-cast polymer solution was immersed in water (after most ox the solvent had evaporated). The polymer film was observed to gel and a transparent, colorless unwarned film separated from the glass plate. The resulting film was soaked for several hours in water to effect extract lion of occluded lithium chloride and solvent, soaked in acetone and dried in a vacuum oven at 90C and 15 mm. pressure.
Refractive index, measured by interferometry,was 1.84.
Stretched polymeric films were prepared in the following manner. Water-swollen films (obtained by soaking the polymer films for several hours for removal ox occluded lithium chloride and solvent as aforedescribed) were cut into strips. The strips were mounted or stretching between e jaws ox a mechanical unidirectional stretcher. Strips were stretched, in some instances, in air at 220C and, in other instance sin boiling ethylene glycol. Elongation ranged from I

60~ to 65~. Infrared dichroism indicated that the films wore less than 65~ oriented The films were optically transparent.
Birefringence, measured tooth the aid of a quartz wedge, was ! ox 390. ~ide-angle X-ray analysis of the bir~fr_n~ent polymer films showed them to be less thin 10~ by weight crystalline.
EXAMPLE
This example illustrates the preparation of posy ~2,2'-dichloro 5,5'-dirnethoxy-biphenylene)-o,o'-dibromo-p,p'-biphenylene dicarboxamide and the preparation therefrom of birc~ringcnt polymeric films.
¦ A Smalley. reaction vessel (a resir.-making kettle equipped with a mechanical stirrer, nitrogen inlet tube and ¦ calcium chloride drying tube) was heated while simultaneously flushing the vessel with nitrogen. After the reaction vessel had cooled to room temperature, 1.5 grams of an hydrous I lithium chloride and 0.6519 gram (0.002082 mole) of sublimed __ .
I 2,2'-dichloro-5,5'-dimethoxybenzidine were added while main-twining positive nitrogen pressure. The reaction vessel was fitted with a thermometer and a rubber stipple and ten mls. o an hydrous distilled N-methylpyrrolidone (NIP) and ten mls. o an hydrous distilled tetramethylurea (MU) were carefully added with the aid of syringes. The resulting mixture was stirred and warmed to 40C until all solids had dissolved. The resulting orange solution was then cooled to a bath of ice and set. to a temperature of 0C. A small amount of lithium chloride precipitation was observed. Recrystallized 2,2'-dibromo-~,4i-biphenyldicarbonyl chloride ~0.9095 gram; 0.002082 mole was quickly added by means or a funnel to the stirred 2,2'-dichloro-5,5'-dimethoxybenzidine solution. An additional ten mls. of MU Nat a temperature of 25C) were adder through-. one funnel to the reaction mixture The temperature or the ,1 .. .

reaction mixture did riot rise above a ~cmpera~urc of okay.
pharaoh stirring for 30 minute.., 'Lowe ~ormatioll ox a clue oust light-yellow, transparent mass (which exhlbi'.ed Strom b refringence but not stir opalesc2nc^) was observed. Syrian was continued for an additional ten minutes at 8C, the stirring was stopped and the ice bath was removed. The tempera-; lure of the reaction mass was observed to rise to SKYE in 15 minutes, and the gal became stiffer in consistency. Heating was immediately commenced and an additional 20 mls. of MU
were added to facilitate dissolution of the reaction mass.
Within 60 minutes the temperature rose Jo 90C and the gel melted to provide a homogeneous, viscous solution.. seating at 90C was continued for two hours while stirring vigorously.
The reaction product, a 2.82~ wt~/vol. light-yellow polymer solution I a trams of polymer per 100 mls. of reaction solvent) was cooled to 40C and the resulting gel-; Tunis, transparent mass was added to 200 mls. of ice-water in a blender. The resulting rubbery solid was filtered and washed (in the blender) twice each with water, acetone and other. The product was dried in a vacuum oven at 15 mm.
pressure and 90C for 18 hours. The product, obtained in 99.3~ yield, was a very pale-yellow fibrous polymeric material having the following recurring structural units:

By OUCH
The inherent viscosity of a polymer solution (0.5 gram or the polymer of Example 4 per 100 mls. of a solution of five ye- my lithium chloride per 100 mls. of dimethylacetamide) was 5.75 diagram at 30C.

Molecular structure was confirmed by infrared spectrose~lJy~ mental allalysis for C2~l118Er2C12N2O4pro-voodooed the hollowing:
I By clue ON %0 Calculated: 49.66 2.68 23.60 10.~ 4.1~ ~.45 ; Found: 49.05 2.~5 23.07 __ 4.15 __ Polymeric films were prepared from the polymeric material of Example 4 by castillg (onto glass plates) solutions of the polymeric material in a I wt./vol. solution of lithium chloride and dimethylacetamide five gyms. lithium , chloride per 100 mls. of dimethylacetamide). The concentra-i lion of polymer was 2% wavily, i.e., two grams of polymer per 100 mls. of the lithium chloride/dimethylacetamide solution.
In each instance, the glass plate carrying the puddle-cast ; 15 polymer solution was immersed in water (after minimal evapora-lion of solvent. The polymer film was observed to gel and a transparent, colorless unorier.ted film separated from the 'j glass plate. The resulting film was Swede for two days in water to effect extraction of occluded lithium chloride and solvent, soaked in acetone and dried in a vacuum oven at 90C
and 15 mm. pressure. Refractive index, measured by inter-formatter was 1.87.
Stretched polymeric films were prepared in the following manner. Watar-swollen films (obtained by soaXir.g the polymer films for several hours for removal of occluded lithium chloride and solvent as a~oredescribed) were cut into strips. The strips were mounted between the jaws of a mechanical unidirectional stretcher. The strips were stretched (in air at 220C) to about 50~ elongation, to I effect film orientation. The stretched films were optically . .

----.

transparent. Birefringerlce, measured with the aid ox a Ayers wedcJc, WAS O . I .
Solutions of the polymer of Example 4, in a concern-traction ox 3 Jo I wavily., in lithium chloride-containing solvents (cog., dimet:hylace~amide containing lithium chloride were found to form colorless, transparent gels which could be melted and r~solidi~icd without thermal degradation. When ho molten solutions were poured into molds or cast into films, solidification was rapid and the solid pieces or films were readily removable. The resulting rubbery solids exhibited high birefringence upon application of very slight stress. Removal ox the stress Wow accompanied by instantaneous disappearance ox he bire~ringent property.

This example illustrates the preparation of posy ~2,2'dibromo-4,4'-biphenylene)-octafluoro-p,p'-bipphenylene dicarboxamide and the preparation therefrom ox birefringent I polymeric films.
;, A 50-ml. reaction vessel (a resin making kettle equipped with a mechanical stirrer, nitrogen inlet tube and calcium chloride drying tube) was heated while simultaneously flushing the vessel with nitrogen Aster the reaction vessel had cooled to room temperature, 1.5 grams of an hydrous lithium chloride and 0.4571 gram (0.00}338 mole of sublimed 2,2'-dibromobenzidine were added while maintaining a positive nitrogen pressure. The reaction vessel was fitted with a thermometer and a rubber stipple and ten mls. of an hydrous distilled N~methylpyrrolidone (NIP) and ten mls. of an hydrous distilled tetramethylurea (MU) were carefully added wl~rl the 1 30 aid of syringes. The resulting mixture was stirred en.
I warmed to 40C until all solids had dissolved. The solely;

=62-lo was n tooled in a bath ox ice and salt to a tcmpera~urc ox 0C. A small amount ox lithium chloride precipitation was observed. Distilled 2,2'~,3',5,5',5,6'-octafluoro-4,4'-biphenylene dicarbonyl chloride ~0.5660 tram; 0.001338 mole) was quickly added by means of a funnel to the stirred, 2,~'-dibromobenzidine solution. An additional ten mls. of 'MOE (a a ~m~era~urc ox 25C) were added wreck the tunnel to the reaction mixture. The temperature of the reaction mixture did not rise above a temperature of 2C. After stirring or 15 minutes, the reaction mixture began to thicken and streaming birefringence (but not stir opalescence) was observed. Stirring was continued for an additional 30 minutes at 4C and the ice bath was removed. The temperature of the reaction mixture was observed to rise to 25C in 40 minutes at which point the reaction solution was slightly viscous and cloudy in appearance. The reaction mixture was warmed gently or 90 minutes with stirring. The temperature of the reaction mixture rose curing the warming to a maximum temperature of 45C at which temperature the reaction solution became homogeneous. Stirring was continued for 18 hours at 45C.
The resulting reaction product, a 3% wt./vol.
polymer solution (three grams of polymer per 100 mls. ox reaction solvent) was cooled to 40C and poured into 200 mls.
of ice-water in a blender. The resulting fibrous solid was filtered and washed (in the blender) twice each with water, acetone and ether. The product was dried in a vacuum oven at 15 mm. pressure and 90C or 18 hours. The product, obtained in 87.6~ yield, was a white fibrous polymeric material having the hollowing recurring structural units C I

The inherent viscosity of a polymer solution (owe cJr~ln ox e polymer of example 5 per 100 mls. of a solution ox live or lithium chloride per loo mls. of dimethylace~amidc) was l.G8 dl./gram at 30C.
Molecular structure was confirmed by infrared spectroscopy. Inspection of the ultraviolet/visible absorb-lion spectrum for the polymer of example 5 (in I wt./vol.
lithium chloride/dimcthylacetamide) showed a Ajax of I no and an absorption peak at 360 no (I = 306).

El~mC~tal analysis or C26l~8Br2F8N22 provided ''t the following:

I OH Brie OF ON OWE
Calculated: 45.11 1.17 23.09 21.97 4.05 4.61 Found: 42.89 1.17 21.86 20.81 3.76 byway di~fcr~lce~
Thermogravimetric analysis showed that onset of degradation of the polymer of Example S occurred at SKYE in nitrogen and at 350C in air. Differential scanning calorie metro showed a reproducible transition at about 15~C.
Polymeric films were prepared from the polymeric material of Example 5 by casting (onto glass plates) solutions of the polymeric material in a I wt./vol. solution of lithium chloride and dimethylacetamide (two grays lithium chloride per 100 mls. of dimethylacetamide)O The concentra-lion of polymer ranged from 0.5 to 5% wt./vol., i.e., from ... . .
0.5 gram to five grams polymer per 100 mls. of the lithium chloride/dimethylacetamide solution. In each instance, the glass plate carrying the puddle cast polymer solution was immersed in water (after minimal evaporation of solvent). The polymer was observed to gel and a transparent and colorless unwarranted film separated from the glass plate The resulting film was soaked for several hours in water to effect extract .

lion ox occluded lithium chloride and solvent, soaked in acutely end dlicd in a vacuum oven at 90C and 15 mm. pressure.
Reflective index, measured by interreromctry was i.74.
; Strc~ched polymeric films were prepared in the following manner. ~ater-swollell films (obtained my soaking the polymer films for several hours for removal of occluded lithium chloride and solvent as aforcdcscribed) ware cut into strips. The strips were mounted between the jaws of a mechanical unidirectional stretcher. The strips were oriented by stretching; (in air at 200C)to an elongation in the range of 50 to 55%. The polymeric strips were optically transparent.
i Birefrin~er.ce, measured with the aid ox a quartz judge, was 0.35. Strips were also stretched in methanol at 25C to an elongation of 55~. Measurement of birefringence for such ; 15 ; stretched films showed a birefrin~ence of 0.44.

This example illustrates the preparation of posy (~,2',3,3'~,4',6,6'-octafluoro-4,4'-biphenylene)caarbohydrazide and the preparation therefrom of birefringent polymeric films.
A 50-ml. reaction vessel (a resin-making kettle equipped with a mechanical stirrer, nitrogen inlet tube and calcium chloride drying tube) was heated while simultaneously flushing the vessel with nitrogen. After the reaction vessel had cooled to room temperature, 1.15 grams of an hydrous lithium chloride and 0.0386 gram (0.001205 mole) of distilled hydrazine were added Chile maintaining a positive nitrogen pressure. The reaction vessel was fitted with a thermometer and a rubber stipple and seven mls. ox an hydrous distilled N-methyl~yrrolidone (NIP) and 12 mls. of an hydrous distilled tetrame~hylure~ (MU) were carefully added with the aid of syringes. The resulting mixture was stirred until most of 7 '11 h' A aye.

the lithium chloride had dissolved. The solution aye thin cooled in a bath of ice and salt to a temperature of 0C. A
small amount of lithium chloride precipitation was observed.
Distilled 2,2',3,3',5,5',6,6'-octafluoro-4,~'-biphen~lenc 5 dicarbonyl chloride (0.5100 gram; 0.001205 mole) was quickly added by means of a funnel to the stirred hydrazine solution.
An additional four mls. of MU (at a temperature of 25C) were added through the funnel to the reaction mixture. The temperature of the reaction mixture did not rise above a 10 temperature ox 5C. The reaction mixture did not thicken and ; stcamin~ bircfrin~Jencc was not ob~crvcd. Lithium carbonate (0.08~0 tram; 0.0024 mole) was added to the reaction mixture, stirring was continued for 30 minutes at 4C and the ice bath was removed. As the temperature of the reaction mixture rose 15 to 25C during the subsequent 60 minutes, the reaction soul-lion first became cloudy and, then, a white precipitate formed.
; Over the next 30 minutes, the reaction mixture was warmed to 40C at which time the reaction mixture became homogeneous.
The reaction temperature was raised to 70C and maintained 20 for one hour. No increase in viscosity was apparent.
The reaction product, a 1.99% wt./vol. polymer solution (1.99 grams of polymer per 100 mls. of reaction solvent) was cooled to 40C and poured into 200 mls. of ice-water in a blender. The resulting powdery solid was filtered and washed (in the blender) twice each with water, acetone and ether. The product was dried in a vacuum oven at 15 mm.
pressure and 90C for 18 hours. The polymeric product, obtained in 95.4% yield, was a white solid material having the following recurring structural units:

-66~

F F F I' i The inherent viscosity of a polymer solution' (0.5 gram of the polymer of Example 6 per 100 mls. of a solution of five grams lithium chloride per 100 mls. of dimethylacetamide) was 1.16 dl./gram at 30C. The molecular structure of the polymer of Example 6 was confirmed by infrared spectroscopy.
Polymeric films were prepared from the polymeric material of Example 6 by casting (onto glass plates) solutions of the polymeric material in a I wt./vol. solution of I, lithium chloride and dimethylacetamide (two grow lithium chloride per 100 mls. of dimethylacetamide). The concentra-lion of polymer ranged from 0.5 to I wt./vol., i.e., from 'I 0.5 gram to five grams polymer per 100 mls. of the lithium chloride/dimethylacetamide solution. In each instance, the grass plate carrying the puddle cast polymer solution was immersed in water (after evaporating the solvent for one hour). The polymer film was observed to gland a physically weak, cloudy and colorless film separated from the glass plate. The resulting film was soaked for several hours in water to effect extraction of occluded lithium chloride and solvent, soaked in acetone and dried in a vacuum oven a 90C and lo mm. pressure. The films were not of sufficient strength to undergo stretching. Refractive index, measured by interferometry,was 1.60.

-This example illustrates the preparation of posy (2,2'-dibromo-4,4'-biphenylene)-t~ p,p'-stilbene dicarbox-aside and the preparation therefrom of birefringent polymeric films.

-67~

250-ml. reaction vessel (a resin-making kettle equipped with a mechanical stirrer, nitrogen inlet tube and calcium chloride drying tube) was heated while simultaneously slushing the vessel with nitrOcJCn. After the reaction, vessel had cooled to room tcmpcratur~, OR grams of an hydrous ; lithium chloride and 2.1~41 grams (0.006269 mole) of sublimed 2,2'-dibromobcnzidine were add while maintaining a positive nitrogen pressure. The reaction vessel was fitted with a thermometer and a rubber stopplc and 45 mls. of an hydrous distilled N-methylpyrrolidone (NIP) and 45 also of an hydrous distilled tetr~methylurea tTMU) were carefully added with the aid of syrinxes. The resulting mixture was stirred and Jo warmed to 40C until all solids had dissolved. The solution was when cooled in a bath of ice and salt Jo a temperature of -5C. A small amount of lithium chloride precipitation was observed. Recrystallized to p,p'-stilbene dicaxbonyl chloride (1.9129 grams; 0.006269 mole) was quickly added by moans ox a tunnel to the stirred 2,2'-di~romobenzidine soul-Al lion. An additional 30 mls. of NMP/TMU mixture (1:1 by weight), at a temperature of 25C, were added through the funnel to thyroxine mixture. The temperature of the reaction mixture did not rise above a temperature of 5C and then dropped rapidly to 3C. After stirring for 30 minutes, the rewaken mixture began to thicken and streaming birefringence (but not stir opalescence) was observed. Lithium carbonate (0~92G gram, 0.01254 mole) was added and stirring was continued for an additional 30 minutes a 0C.
The ice bath was removed from the reaction vessel, and when the temperature reached 20C yin 30 minutes), tune reaction solution had become sufficiently viscous as to begin I
!

it `
to climb the shaft of the mechaslical circa A maximum Rio t~n-i~cra~ul-c of 55C way reached. Stirring was stopped and the mixture was heated overnight at a temperature of 55C. The reaction product a viscous polymer solution ox 3% wt./vol. concentration (three grams of polymer per 1~0 mls of reaction solvent) was diluted with 130 mls. of I wt./vol.
lithium chloride in dimethylacetamide. The resulting polymer solution was poured into 200 mls. of ice and water in a blender. The resulting fibrous solid was filtered and washed (in the blender) twice each with water, acetone and ether.

The product was dried in a vacuum oven at 15 mm. pressure and 90C or 18 hours. The polymeric product, obtained in 100%
yield, was a vex light-yellow fibrous solid having the following recurring structural units:
,.

C C = I C-N N

By The inherent viscosity of a polymer solution (0.5 gram of the polymer of Example 7 per 100 mls. of a solution of five grams lithium chloride per 100 mls. of dim ethyl-assumed) was 9.04 dl./gram at 30C. The molecular weight , 20 of the polymer, as determined by light smatterings, was ¦ , 1.95 x 106, and be gel permeation chromatography, 8.71 x 105.
the molecular structure OX the polymer was confirmed ¦ l by infrared spectroscopy. Inspection of the ultraviolet/visible spectrum of the polymer (in 5% wt./vol. lithium chloride' 1 25 dimethylacetamide~ showed a Max ox 352 no (E = 66,000) j ire absorption peak at 368 no (I = 52,~00) and an extremely woe.

tail at 400 no.

~lcmcntal analysis for I r2N2O2 provided philology:
~C Libra ON JO
I, Calculated: 5~.56 3.1627.83 ~.88 5.57 Found: 5~.50 3.2227.94 4.87 5.47 (by difference) Thermog~-avime~ric analysis showed that the onset of degrada~ioll of ho polymer of example 7 occurred at 470C in nitrogen and at 515C in air. Differential scanning calorie metro and thermal mechanical analysis of film samples detected a reproducible transition at about 225C.
Polymeric films were prepared from the polymeric lo material ox Example 7 by casting (onto glass plates) solutions of the polymeric material in a I wt./vol. solution of lithium chloride and dimethylacetamide (five grams lithium chloride per 100 mls. of dimethylacetamide). The concentration of polymer ranged prom l to 5% wt./vol., i.e., from one gram to five grams polymer per lo mls. of the lithium chloride/dimethylacetamide ; solution. In each instance, the glass plate carrying the puddle-c~st polymer solution was immersed in water wafter minimal evaporation o. solvent). The polymer was observed to gel and a transparent and colorless unwarranted film separated from the soaked glass plate. The resulting film was soaked for several hours in water to effect extraction of occluded lithium chloride and solvent, soaked in acetone and dried in a vacuum oven at 90C and 15 mm. pressure. Refractive index, measured by interferometry,was 2.03.
Stretched polymeric films were prepared in the following manner. Water swollen films (obtained by soaring the polymer films for several hours for removal of occluded lithium chloride and solvent as a~oredescribed) were cut Lowe strips. The strips were mounted between the jaws of a mechanical unidirectional stretcher. The strips were Starr !
- 7 o -., ... , . , .. . . . . . .. . . _ .... _ . _ ...
_,. I, ,_. .

(in air at 220C) to about 55 to 55~ elongation, to coquette film oricn~a~iol~. The stretched films jerk optically runs parent. Infrared dichroism indicated that the stretched films crook less than 65~ by weicJht oriented, the modulus was 3~9 x 106 pi Wide-angle X-ray analysis ox the films showed crystallinity to be less than 10% by weight. Bircfrin-Al genre, measured with the aid of a quartz wedge, was 0.589.
! Solutions of thy polymer of Example 7 in lithium chloride/dimethylacetamide, as aforedescribed, were formed into extruded films by tile "wc~-jct" method whereby the soul-lion of polymer is extruded into an aqueous coagulation bath I for golfing of the polymer material. The resulting trays parent, colorless film strips were soaked in water and cut to about 1 Jo 2 inches ( 25.4 to 50.8 mm.) for testing. The partially oriented strips of film produced by the extrusion I were further oriented by stretching in the manner described; in the Examples hereof Stretching was effected in air at a temperature ox 180C. Elongation was to the break point, in ; the range of about 40~ to So the stretched strips were optically transparent. Infrared dichroism indicated that the films were 85% oriented. Measurement of birefringence utilizing i a quartz wedge provided a birefringence value of 0.977. Measure-mint my resort to interferometry provided a value of 0.865.
EXAMPLE
1 25 This example illustrates the preparation of posy (2,2'-dibromo-4,4'-biphenylene~-_rans- -bromo-biphenylene I dicarboxamide and the preparation therefrom of birefringnet ¦ polymeric films ¦ A 50-ml. reaction vessel (a resin-making kettle ¦ 30 equipped with a mechanical stirrer, a pressure-equalizing dropping funnel, a nitrogen inlet tube and calcium chlsri~e -71~

L

drainage Tokyo was h~2tcd Chile simul~alleously Lang the vessel with nitrogen. After the reaction vessel had cooled owe room temperature, 1.5 grams of an hydrous lithium chloride and 0.4779 gram ~0.001397 mole) of sublimed 2,2'-dibromo-i 5 benzidine were added while maintaining a positive nitrogen pressure. The reaction vessel was pitted with a thermometer and a rubber supply and it mls. of an hydrous distilled N-methylpyrrolidinone (NIP) and five mls. of an hydrous distilled tetramcthylurea (MU) were carefully added with the aid of I syringes. The resulting mixture was stirred and warmed to 40C until all solids had dissolved. The solution was then cooled in a bath of ice and salt to a temperature of 0C. A
small amount of lithium chloride precipitation was observed.
Recrystallized ~-bromo-p,p'-stilbene dicarbonyl chloride (0.5366 gram; 0.001397 mole) was quickly added by means of a funnel to the stirred 2,2'-dibromobenzidine solution An additional ten mls. of MU (at a temperature of 25C) were added through the funnel to the reaction mixture. The tempera-; lure of the reaction mixture did not rise above a temperature of 4C. After stirring for 15 minutes, the reaction mixture began to thicken and streaming birefringence (buy not stir opalescence was observed. Stirring was continued for an additional 30 minutes at 4C.
The ice bath was removed from the reaction vessel and the temperature was observed to rise to 25C in 90 minutes at which point the reaction mixture had become sufficiently viscous as to climb the shaft of the mechanical stirrer. Over the next 90 minute, the very pale-yellow reaction mass was gently warmed with intermit tat stirring the maximum temperature reached was approximately 70C.

:
; The reaction product, a I wt./vol. ~olyllleL oily (three yearns ox polymer per 100 mls. of reaction solvcn~) was ; cooled to 40C and poured into 200 mls. of ice-water in a j blender. The resulting fibrous solid was filtered and washed (in the slender) twice each with water, acetone and ether.
The product was dried in a vacuum oven at 15 mm. pressure ¦ and ~0C or 13 hours. The product, ob~aincd in 95.4!~ yokel, I, was a light-yellow fibrous polymeric material having the following recurring structural units:
o If The inherent viscosity ox a polymer solution (0.5 gram of the polymer ox Example 8 per 100 mls. of a solution of five grams lithium chloride per 100 mls. of dim ethyl-acetamide) was 7~81 dl./gram at 30C.
Molecular structure was confirmed by infrared spectroscopyO Elemental analysis for C28H17N2Br3O2 provided the following:
I _ OH _ Brie ON JO
Calculated: 51.478 2~604 36.724 4.289 4.90 Found: 51.17 2.80 34.~2 4.15 7~06 my doffers) Polymeric films were prepared from the polymeric material of Example 8 by casting (onto glass plates) solutions ox the polymeric material in a 5% wt./vol. solution of lithium chloride and dimethylacetamide (five crams lithium chloride per 100 mls. of dimethylacetamide). The concentration of polymer ranted from 0.5 to I wt./vol., i.e., from 0.5 gram to 5 grams polymer per 100 mls. of the lithium chloride/
dimethylacetamide solution. In each instance, the glass plate carrying the puddle-cast polymer solution was immersed in water (after minimal evaporation of solvent). The polymer _ .1 was observed Jo gel and a transparellt and colorless unranked film separated prom tic socked lass plate. Tile rc~ultillg film was soaked for several hours in waler Jo effect extraction of occluded lithium chloride and solvent, soaked in acetone and dried in a vacuum oven at ~0C and 15 mm. pressure.
Refractive index, measured my inter~exomctry, was 2.07.
Stretched polymeric films were prepared in the following manner. Watcr-~wollcn films (obtained by soaking the polymer films for several hours for removal of occluded lithium chloride and solvent as aforcdcscribed) were cut into strips. Toe strips were mounter between the jaws of a mechanical unidirectional stretcher. The strips were stretched (in air it 220C) to about 60~ to 65~ elongation, to effect film orientation. The stretched strips were optically trays-parent. Birefringence, measured with the aid of a quartz wedge, was 0.680.
Solutions of the polymer of Example 8 in lithium chloride/dimethylacetamide, as aforedescribed, were formed into extruded films by the "wet-jet" method whereby the solution ox polymer is extruded into an aqueous coagulation bath for golfing ox the polymer material. the resulting transparent, colorless film strips were soaked in water and cut to about 1 to 2 inches (25.4 to 50.8 mm.) for testing. The partially oriented strips of film produced by the extrusion were further oriented by stretching in the manner described in the Examples hereof. Stretching was effected in air (at a ~empcra~ure ox 180C) Jo the break point, in the range ox about 40% to 50~ elongation. The stretched film strips were optically transparent. Measurement of birefringence utilizing a quartz wedge provided a birefringence value of 0.~55. Measure-mint my resort to interferometry provided a value of 0.849.

t .
This example illustrates true preparation of posy ` (2,2'-dibromo-4,4'-biphenylene)-~,a'-dimethylmuconnomad and ! the preparation therefrom of birefringent polymeric films A 50-ml~ reaction vessel (a resin-making kettle quipped with a mechanical stirrer, a pressure-equalizin~
f~rGplJin~J urea at, a rli~rocgcl~ inlet lube, and calcium chloride drying tube) was heated while simultaneously flushing the v~s~l with ni~roycn. After the reaction vessel had cooled to room temperature, C.4 gram of an hydrous lithium chloride lo all 0.8519 gram ~0.00249 mole) of sublimed 2,2'-dibromo-benzidine were added while maintaining a positive nitrogen pressure. The reaction vessel was fitted with a thermometer ; a rebuker stipple, and ten mls. of alluders distilled N-me1-hylpyrrolidone to P) we're carefully added with the aid of a syringe. The resulting mixture was stirred and warmed Tokyo until all solids had dissolved. The solution was then cooled in a bath of ice and salt to a temperature of OKAY with format ion of ohmic, lithium chloride,_, precipitate. A solution or wrecker-tallied dim ethyl muconyl chloride gram; 0.0024,91 mole) in six mls. of an hydrous, distilled tetrahydrofuran(T~F) was added to the dropping funnel through a rubber stopper with a syringe. The dim ethyl muconyl chloride/THF solu~lon, the temperature of which was 25C, was added drops o'er five minutes to the cold 2,2'-dibromobenzidine solution white ~tirrincJ~ moderately. The addition funnel was rinsed w oh six my Or' Nil' which was alto addled dropwisc to ho rcic~_io, ix,;urc ill order to prevent the temperature of the rcacsio~
mixture from rising above 1C. After stirring for one Gore Jo during which time the solution turned lemon-yellow us did not thicken), 0.354 gram of solid lithium carbonate way added I

¦ all at once Jo ho reac~icn mixture. Within ten minutes `! nuzzle ~hickeninc~ was observed and after an additional , I minutes, at 20C, the viscosity increased further. The ' ice bath was removed from the reaction vessel and the tempera--lure of the reaction mixture was allowed to rise to 25C over a one-hour period during which time a thick paste Lowe wormed. 'Lowe ~empcrature ox the reaction mixture was I increased Jo 65C over the next 20 minutes producing a mix~urc Welch could no longer be stirred. Additional heating for 18 hours at 55C without stirring produced a transparent, Lyle viscous polymer solution. The reaction product, a 5.36~ wt./vol. polymer solution (5.36 grams of polymer per 100 mls. of reaction solvcn~) was observed to exhibit con-siderable streaming birefringence upon application of low ' 15 mechanical stress; stir opalescence was not, however, observed.
I The polymer solution was poured into a blender ;' COntaininCJ 200 ml. ox ice-wa~cr and the resulting; fibrous solid was filtered and washed (in the blender) twice each i with water, acetone and ether. The product was dried in a vacuum oven at 15 rum. pressure and 90C or 13 hours. The product, obtained in 94.7~ yield, was a white fibrous polymeric nla~crial having the following; recurring structural units:
13 if if o if r t C - C = C -- C = C -- C -- N N
SHEA By 'I C inhere Vim ox my old a polylne~r solute ion (owe grams of the polymer of Example 9 per 100 mls. ox a solution of five grams lithium chloride per 100 mls. or dilnc~hylacc~amidc) was Go dl./gram at 30C.

I

Molecular structure was confirmed by infrared I¦ spec~roscopy. Inspection of the ultraviolet/visible absorption ! spectrum for the polymer of Example 9 (in 3j wt./vol. lithium chloride/dimethylacetamide showed a Max I 333 no = 33,600) and an extremely weak tail at 400 no.
Elemental analysis for Clue 3r2~l22 P
, Jo 1 tow i~lCJ:
¦ I OH Brie ON JO

Calculated: 50.448 3.387 33.562 5.883 6.72 Issue 50.0~ 3.~5 3~.17 5.7~ Go (my ~i~Ecr~-,c~
hcrmogr?vime1ric analysis showed what the onsc~ ox degradation occurred at 360C in ni~rogcn and at 310C in air.
Differential scanning calorimetry and thermal mechanical i~n~lysis of film samples showed a reproducible transition at about 185C.
Polymeric films were prepared from the polymeric material ox Example g by casting (onto glass plates) solutions ox tune polymeric material in a I wt./vol. solution of lithium chloride and dimethylacetamide (five grams lithium chloride per 100 mls. of dimethylacctamide). The concentration ox polymer ral~g~d prom 2 to Jo wavily., i.e., from two grams to four yams polymer per 100 mls. of the lithium chloride/
dllllo~llylac~alnide slyly. in each instance, the glass pluck carrying the puddle cast polymer solution was immersed in water (after minimal evaporation of solvent). The polymer film was observed to gel and a transparent and colorless ulloriell~ed film separated prom the glass plate. The resul~inc3 Film was socked for several hours in water to effect cx~rac-Shea of occluded lithium chloride and solvent, soaked 30 Salk and dried in a vacuum oven at 90C and 15 on. wrier.

Refractive index, measured by interferometry,was 1.~1.

s Lo ¦ Stretched polymeric films were prepared in the ! ~ollowil~c; manner. Water-swollen films (obtained by soaking ¦ the polymer films for several hours for removal of occluded I lithium chloride and solvent as aforedescribed) were cut into ¦ 5 strips. The strips were mounted between the jaws of a ccll~nic~ reacher and were unidirectionally stretched, ,¦ ~ucco~ivcly, in steam, acc~onc and boiling e~hylcnc ylycol (all of which function as plasticizers). The strops were ¦ stretched to an elongation of from 35% to 45~. The film trips LO were further elongated (up to 60~) by stretching in air at , 200C. Thy stretched strips were optically transparent. Optical ;, retardation was measured with a calibrated quartz wedge; film thickness was measured with a micrometer. Birefringence, I measured by means ox a quartz wedge, was 0.40.

, For purposes of comparison with the substituted i polyamides of the present invention, an unsubstituted polyp a e was prepared and evaluated in the following manner.
i A solution polymerization reaction for the production of poly(p-benzamide) was conducted in accordance with the hollowing reaction scheme:
O
O = S = N C Of Lick Lowe- >

n ¦ A 50-ml~ reaction vessel (a resin-making kettle ¦ e~lull~le~ with rnech2nical stirrer, nitrogen filet lube an calcium chloride drying tube) was heated while sommeliers I
¦ Lowe he vessel with nitrocJen. After the recline vex i had cooled to room temperature, 40 mls. of an hydrous d~s~lllec era methyl urea (TAO), 8.0~ trams (0.04 mole) of vacuum-¦ distilled p-thionylaminobenzoyl chloride and 0.52 yam 1 (0.012 mole) of lithium chloride were added while Mouton;
'I a positive nitrogen pressure. The resulting reaction mixture Al 5 was stirred for ten minutes at room temperature and l.G8 yearns (0.0~ mole) of lithium hydroxide MindWrite were added white vigorously stirring. The reaction mixture was when stirred or one hour at room temperature. After a period of seven additional minutes, the reaction mixture became cloudy an we_ o~rvcd Jo ~hickcn. the L~olymcric reactiorl product, Err 20 milks, tl~ickcncd su~icicntly Jo adhere ho aye of the mechanical stirrer. Tory only hour, the reaction mixture, which could not be stirred, was heaved. on additional flu y (14 my ox 'Lou way added a which point the I reaction mixture still could not be stirred. The reaction mixture was then heated Jo 130C without stirring. After , two hours of heating at 130C, pliability of polymeric I iOJl 111~ increased an ho product appeared to have partially dissolved. Two reaction product was stored in the reaction vessel overnight and was washed with water, filtered and washed with acetone then ether. The product, posy (p-bcn~amide) was dried in a vacuum oven at 80~C or two hours, The inherent viscosity of a polymer solution of poly(p-benzamide) in sulfuric acid was 1.60 dl./gram at 30C.
I Polymeric Elm of poly(p-bcnzamidc) were prepared by casting a solution of the polymeric material in a 56 wt./vol.
solution of lithium chloride and dimethylacetamide (five trams lithium chloride per 100 mls. of dimethylacetamide). The concentration of polymer was 5Q~ wt.jvol., i.e., five yam JO l.olymcr par 100 also ox the lithium chloride/dime~hyl~cetaml~e solution. The cast polymer film was dried in a vacuum oven a 90C (30 in. Hug) overnight. The polymer film was an opaque, White flexible film Additional films were formed by puddle-casting the solution as a~orcd~scribed onto glass plates In each instance, the glass plate carryincJ the puddle-cast polymer solution was immersed in water (after most ox the solvent had evaporated). The polymer film which separated from the glass plate was a tough, transparent, ~lcxiblc film. The resulting film was sucked or several 10 hours in waxer to effect extraction of occluded lithium chloride and solvent.
Stretched polymeric ills were prepared if, the ~ollowislcJ manner. Wa~cr-swollcn films (obtained by oily the polymer films or several hours or removal of occluded lithium chloride and solvent as aforedescribed) were cut into strips. The strips were mounted between the jaws ox a mechanic eel richer aloud ware unidirectionally s~re~ched, successively, in skim and in air (at 200C). The strips were stretched to an elongation of approximately pow. The resulting stretched films ware clouded in appearance. Optical retardation was measured with a calibrated quart wedge; film thickness WAS
measured with a micrometer. Birefringence, measured by means ox a quart wedge, was 0.23.
By inspection of ho valves ox biro ~ringc:s,cQ
described it coslnection with the substituted polyamides of Lo TV Lo ' I ; ho I
it can be seen that the birefringence of poly(p-bcn~.~midc) of collpar~tive ~xaml~le 10, was, in general, decidedly lower.

-80~

I~XAM?LE: 11 I This employ illustrates the pxeparatlon Go polo-;! [2,2'-bis(trifluoromethyl)-4,4'-biphenylenc]-transsup stilbene dicarboxamide and the preparation therefrom of birefringent polymeric films.
loo rnl. rcac1:ion vassal (a rcsin-makinc~ kc~tlc ¦ equipped with a mechanical stirrer, nitrogcll into lube and calcium chloride drunk tube) was heated while simultaneously flushing the vessel with nitrogen. After the reaction vessel ha cooled to room tcmpcra~urc, 1.5 Crimea of an hydrous lithium chloride and 0.5171 gram (OKAY mote) of recrystallized ¦ 2,2'-bis(trifluoromethyl)-benzidine were added while main twining a positive nitrogen pressure. The reaction vessel was it'd with a thermometer end a rubber stol~plc and ten mls.
of an hydrous distilled N-methylpyrrolidon~ (NIP) and ten mls.
of an hydrous distilled tetramethylurea (MU) were carefully I added with the aid of syrinxes. The resulting mixture was stirred and warmed to 40C until all solids had dissolved.
The solution was then cooled in a bath of ice and salt to a I temperature of -5C. A smell amount of lithium chloride precipitation was observed. ~ccrystalli~cd trans-p,p'-stilbene dicarbonyl chloride (0.4923 gram; 0.001615 mole) was carefully added by means of a funnel to ho stirred 2,2'-bis(trifluoromcthyl)-ben~idinc solution. on additional 10 mls.
of MU, at a temperature of 0C, were added through the funnel to the reaction mixture. Tic temperature of the reaction mixture did not rise above a temperature of 5C and then roll rapidly to -3C. r s~irril~cJ or 30 monks, the reaction mixture began to thicken and streaming birefringence (but not stir opalescence) was observed. Stirring was continued for an additional 30 minutes at 0C.

-81~

The ice bath was removed from the reaction vessel, an when the temperature reached 20C (in 30 minutes), the reaction solution had become very viscous. Over the next 75 minutes, the completely colorless, transparent solution was warmed to 72C. After stirring at this temperature for the Nat 18 hours, the mixture was cooled to 40C. The resulting polymer solution was poured into 200 mls. of ice and water in a blender. The resulting fibrous solid was filtered and washed (in the blender) twice each with water, acetone and ether. The product was dried in a vacuum oven at 15 mm. pressure and 90C
' for 18 hours. The polymeric product, obtained in 99.5% yield, was a very liqht-yellow fibrous solid having the following recurring structural units:

C C = C I} I

i 15 Thy inherent viscosity of a polymer solution (0.5 gram of the polymer of Example 11 per 100 mls. of a solution ox jive grams lithium chloride per 100 mls. of dim ethyl-acetamide) was 4.735 dl./gram at ~0C. The molecular structure of the polymer was confirmed by infrared spectroscopy.
Elemental analysis for C30H18F6N2O2 p ~ollowill~J:
I Al Jo ON I
Calculated: 65.22 3.28 20.64 5.07 5.79 Found: 64.54 3.76 19.04 4.85 7.81 (by difference) 'l'hermogravimetric analysis showed that the onset ox degradation of the polymer of Example 11 occurred at 500C ii, I nitrogen and at 410C in air. Differential scanning Clara-! metro and thermal mechanical analysis of film samples dctcc~c~i a reproducible transition at about 185C.

-82~

Polymeric films were prepared from the ~ol~Jmcric material of Example 11 by casting (onto glass plates) solutions of tune polymeric material in a 5% wt./vol. solution of lithium chloride and dimethylacetamide (five grams lithium chloride per 100 mls. of dimethylacetamide). The concentration ox polymer ranged from 1.0 to I wt./vol., i.e., from 1.0 gram to five grasps polymer per 100 mls. of the lithium chloride/
Al dimethylacetamide solution. In each instance, the gloss plate 'I carrying the puddle-cast polymer solution was immersed in water l 10 (attacker minimal evaporation of solvent). The polymer film was if observed to gel and a transparent and colorless unwarranted film separated from the glass plate. The resulting film was soaked for several hours in water to effect extraction of ¦ occluded lithium chloride and solvent, soaked in acetone and dried in a vacuum oven at 90C and 15 mm. pressure. Refractive index, measured by interferometry, was 1.997.
I Stretched polymeric films were prepared in the I lollowill~ millionaire. Water-swollen films (obtained by soaking the polymer films for several hours for removal ox occluded lithium chloride and solvent as aforedescribed) where cut into strips. The strips were mounted between the jaws of a o~lla~lical ul~idirectiol~al stretcher. 'Lowe strips were stretched (in air at 220C) to about 60 to 65% elongation, to effect ! film orientation. The stretched films were optically trueness parent. Birefringence, measured with the aid of a quartz wedge, was 0.537.
Solutions of the polymer of example 11 in lo us chloride/dimethylacetamide, as aforedescribed, were formed into extruded films by the "wet-jet" method whereby the Swahili lion of polymer is extruded into an aqueous coagulation bath Jo I
for golfing OX the polymer material. The resulting trays-L~ren~, colorless film strips were soaked in water and cut to about 1 to 2 inches (25.4 to 50.8 mm.) for testing. The aureole oriented strips of film produced by the extrusion wore further oriented by stretching in the manner described on the Examples hereof. Stretching was effect to an elongation I of less than 20~. The stretched strips were optically trays-Z parent. Infrared dichroism indicated that the films were 92 Al oriented. Measurement of birefringence utilizing a quartz wedge provided a birefringence value of 0.879.

This example illustrates the preparation ox polyp 'I [2,2'-bis(trifluoromethyl)-4,4'-biphenylene]-2,2'--dimethoxy-I ~,4'-biph~nyl and tune preparation thcrcErom of bircfrin~ent polymeric films.
' A 100 ml. reaction vessel pa resin-making kettle j equipped with a mechanical stirrer, a pressure-equalizing I drop in funnel, a nitrogen inlet lube all calcium chloride ! dry lube) was healed white simul~ancously flushing the Z 20 vessel with nitrogen. After the reaction vessel had cooled to room temperature, 3.0 grams of an hydrous lithium chloride aloud 0.4328 yam (0.001352 mote) of recrystallized 2,2' bus (trifluoromethyl)benzidine were added while maintaining a ¦ positive nitrogen pressure. The reaction vessel was fitted with a thermometer and a rubber supply and 20 mls. of ashy-dross distilled N-methylpyrrolidinone (NIP) and 20 mls. of j an hydrous distilled tetramethylurea (MU) were carefully added! w i l h the aid of .syrin~Jcs. The resulting mixture was stirred and warmed to 40C until all solids had dissolved. The Swahili ion WAS howl cooled in a bath of ice and so to a ~cm;~cra~urc ' I

or or C. A mull amount of lithium chloride precipitation was observed. recrystallized 2,2'-dimethoxy-4,4'-biphcnyldicarbonyl chloride (0.4586 gram; 0.001352 mole) was quickly added by means of a funnel to the stirred 2,2'-bis(trifluoromcthyl)-I bcl~idille solutioll. on additional 20 mls. of MU (at temperature of 0C) were added through the funnel to the reaction mixture. The temperature of the reaction mixture did not rise above a temperature of 5C. After stirring for 30 minutes, the reaction mixture began to thickly all turned milk-like in appearance. Stirring was continued for an additional 30 minutes at 0C.
Thy ice bath was removed from the reaction vessel and the temperature was observed to rise to 20C in 30 minutes at which point the reaction mixture was viscous and opaque.
Over the next 75 minutes, the opaque reaction mass was gently warmed to 40C at which point it became transparent. After stirring at this temperature for the next 18 hours, the reaction mixture was cooled to 30C and poured into 400 mls.
of ice-water in a blender. The resulting fibrous solid was j]~rcd and washed (in the lander twice each with water and ether. The product was dried in a vacuum oven at 15 mm. pressure and 90C for 18 hours. The product, obtained in 99.3% yield, was an off-white fibrous polymeric material exhibiting syllable in acetone or tetrahydrofuran and having the following recurring structural units;

The inherent viscosity of a polymer solutioil I awry of the polymer of ample I per 100 mls. ox sOlUtlOf: Al- ' lo trams lithium chloride per 100 mls. of dimethylacetamide) was lug dl./gram aye 30C.
Molecular structure was confirmed by infrared spectroscopy. Inspection of the ultraviolet visible spectrum of the polymer (in I wt./vol. lithium chloride/dimethyl-Eormamide) showed a Max of 316 no (I = 2-59 x 10 )-Elemental analysis for C30H20F6N2O4 p following:

I OH OF ON JO
alkaloid: 61.34 3.43 19.41 4.77 10.89 Found: 59.82 3.51 18.70 4.62 13.35 (by difference) Thermogravinetic analysis showed that the onset of degradation of the polymer of Example 12 occurred at 470C in nitrogen and at 440C in air. Differential scannincJ colon-lo metro detected a reproducible transition at about 180C.

Polymeric films were prepared from the polymeric material of Example 12 by casting (onto glass plates) solutions ox the ~olymcric malarial in a I wt./vol. solution of lithium chloride and dimethylacet~mide ivy grams lithium chloride or 100 my ox dimethylacetamidc). The concentration of polymer ranged from I to So wt./vol., it from lug gram to 5 trams polymer per 100 mls. of the lithium chloride/
dimethylacetamide solution. In each instance, the glues slate c~rryl~cJ the pud~lc-cast polymer solution was immersed in water (aster minimal evaporation of solvent). The polymer was observed Jo gel and a transparent and colorless unwarranted film separated from the soaked glass plate. The resultincJ
film was soaked or several hours in water Jo effect extraction of occluded lithium chloride and solvent, soaked in acetone and dried in a vacuum oven at 90C and 15 mm. pressure.
l~c~rac~ivc index, measured by interferometry, was 1.7;~

¦ Solutions of the polymer of example 12 in Lithuania I chloride/dlmethylacetdmidc, as a~oredescribed, wore formed into extruded illume by the "we~-jc~" method whereby the I solution or polymer is extruded into an aqueous coagulation 5 byway or elan of the polymer material. The resulting transparent, colorless film strips were soaked in water and cut to about 1 to 2 inches (25.4 to 50.8 mm.) for testing. The partially oriented strips ox film produced by the extrusion ! were further oriented by stricken in the manner described in the Examples hereof. Stretching was effected in air (at a ! temperature of 180C) to an elongation of less than 20~. The stretched film strips were optically transparent. Infrared ! dichroism indicated that the films were 92% oriented. Measure-mint of birefringence utilizing a quartz wedge provided a i 15 bircfrin~ cc value of 0.586.

! AMPLE 13 This example illustrates the preparation of polyp [2,2',3",2"'-tetrakis(trifluoromethyl)-1,1':4',1"::4",1"':4"'-~uatcrphenylene]-trans-p,p'-stilbenedicarboxamide and the preparation therefrom of birefringent polymeric films.
A 100 ml. reaction vessel (a resin-making kettle equipped with a mechanical stirrer, nitrogen inlet tube and calcium chloride drying tube) was heated while simultaneously flushing the vessel with nitrogen. After the reaction vessel I had cooled to room temperature, lo grams of an hydrous lithium chloride and 0.5806 gram ~0.0009543 mole) of recrystallized 4,4"~diamino-2,2',3",2"'-~etrakis(trifluoromethyl))-1,1':4', 1":4",1"'-quatcrphcnyl ware added white maintaining a IJositivc nitrogen pressure. The reaction vessel was fitted with a ~hernlolnc~cr and rubber ~Oi~plc and ten mls. ox an hydrous I

.~æ~

distilled N-methylpyrrolidone (NIP) and ten mls. of an hydrous distilled tetrame~hylurea (MU) were carefully added with the aid of syringes. The resulting mixture was stirred end warmed to 40C until all solids had dissolved. The solution was then cooled in a bath of ice and salt Jo a temperature ox -5C. A
small amount of lithium chloride precipitation was observed.
~ccry-~tallL~ed ~ran_-p,p'-s~ one dicarbonyl chloride (0.2909 gram; 0.0009543 mole) was carefully added by means of a funnel Jo the stirred diaminoquaterphenyl solution. An additional 10 mls. ox MU, at a temperature of 0C, were added through the funnel to the reaction mixture. The temperature of the reaction mixture did not rise above a temperature of 7C and then dropped rapidly to KIWI After stirring for 30 minutes, the reaction mixture began to thicken and streaming birefringence (but not stir opalescence was observed. Stirring was continued for an additional 30 minutes at 0C.
The ice bath was removed from the reaction vessel, and when the temperature reached 20C (in 30 minutes), the reaction solution had become very viscous. Over the next 75 minutes, the light yellow, opaque solution was warmed to 45C.
After stirring at this temperature for the next 18 hours, the transparent polymer solution was poured into 200 mls. ox ice and water in a blender. The resulting fibrous solid WAS filtered and washed (in the blender) twice each with water and ether.
Lowe product was dried in a Vacuum oven at 15 mm. pressure and 90C for 18 hours. The polymeric product, obtained in 92.2%
yield, was a very light-yellow fibrous solid having the lolJowjn(J recurring structural units:

Jo I! I = C C-N H

lo The inherent viscosity of a polymer solution ~0.5 gram of the polymer of Example 13 per 100 mist of a solution ox five grams lithium chloride per 100 mls. of dimethylacetamide) was 1~31 dl./gram at 30C. The molecular structure of the polymer was confirmed by infrared spectroscopy. The polymer was soluble in tetrahydrofuran, in acetone and in various aside-type solvents, with and without added lithium chloride.
Elemental analysis for C~4H2~F12N2O2 p following:
I OH OF ON %0 ___ __, Calculated: 62.86 2.8827.12 3.33 3.81 Found: 62.07 3.2924.18 3.16 7.3, (by difference) Thermogravimetric analysis showed that the onset of degradation of the polymer of Example 13 occurred at 510C in nitrogen and at 440C in air. Differential scanning calorie metro and thermal mechanical analysis of film samples detected a reproducible transition at about 187C.
o]ynlcric film ware ~rcl~rcd prom the polymeric material of Example 13 by casting (onto glass plates) solutions of the polymeric material in a I wt./vol. solution of lithium chloride and dimethylacetamide (five grams lithium chloride per 100 mls~ of dimethylacetamide). The concentration of polymer ranged from 0.5 to I wt./vol., i.e., from 0.5 gram to five grams polymer per 100 mls. ox the lithium chloride/dimetAyl-acetamide solution. In each instance, the glass plate Corinth puddle-cast polymer solution was immersed in water (after inilllal ~vaL~ra~ion ox solvcn~). 'Lowe ~olymcr film was observe to gel and a transparent and colorless unwarranted film separated prom the glass plate. The resulting film was soaked for several hours in water to effect extraction of occluded lithium chloride and solvent, soaked in acetone and dried in a vacuum oven a 90C and 15 mm. pressure. Refractive index, measured by inter-~erometry, was 1.810.

Jo Lo Stretched polymeric films were prepared in the ~ollowiny manner. Water-swollen films (obtained by soa~incJ
the polymer films for several hours for removal of occluded lithium chloride and solvent as aforedescribed) were cut into strips. The strips were mounted between the jaws of a mechanical unidirectional s~rctchcr. 'Lowe strips were stretched in methanol and then in air at 220C to effect film orientation. The stretched films were optically transparent. Birefringence, measured with the aid of a quartz wedge, was 9.87.

This ex~nple illustrates the preparation of polyp [2,2',3",2"'-tetrakis(trifluorome~hyl)-1,1';4',1";;4",1"';4"'-quaterphenylene~terephthalamide and the preparation therefrom ox birefrin~ent polymeric films.
A 100 ml. reaction vessel (a resin-making settle equipped with a mechanical stirrer, nitrogen inlet tube and calcium chloride drying tube) was heated while simultaneously Lange eye vessel with nitrogen. After the reaction vessel hod cooled to room temperature, 1.5 grams of an hydrous lithium chloride and 0.6301 gram (0.001036 mole) of recrystallized 4,4"'-dianlino-~,2',3",2"'-tetrakis(trifluorQmethyyule, 1":4",1"'-quaterphenyl were added while maintaining a positive nitrogen pressure. The reaction vessel was fitted with a tllcrlllom~e~r art rubber Swahili and con mls. of an hydrous ~3is~illcc] N-mcthyl~yr~olidonc NO and ion mls. of an hydrous distilled tetramethylurea (TAO) were carefully added with the air of ~yrinyc~. the resulting mixture was stirred and warmed to 40C until all solids had dissolved. The solution was then cooled in a bath of ice and salt to a temperature of +5C.
A small amount of lithium chloride precipitation was observed.

Recrystallized ~erephthaloylchloride (0.2103 gram; 0.001036 mole) was carefully added by means of a funnel to the stirred ?, 2'-diaminoquaterphenyl solution. An additional 10 mls. of MU, a a temperature of 10C, were added through the funnel to the reaction mixture. The temperature of the reaction mixture did not rise above a temperature of 10C awry then dropped to 15C. After stirring for 30 minutes, the reaction mixture began to thicken and streaming birefringence (but not stir opalescence) was observed. Stirring was continued for an additional 30 minutes at 10C.
The ice bath was removed from the reaction vessel, and when the temperature reached 27C (in 30 minutes), the reaction solution had become very viscous. Over the next 75 minutes, the light yellow, transparent solution was warmed to 40C. After stirring at this temperature for the next 18 hours, the polymer solution was poured into 200 mls. of ice and water in a blender. The resulting fibrous solid was filtered and washed (in the blander) twice each with water and ether. The product was dried in a vacuum oven at 15 mm. pressure and 90C
for 18 hours. The polymeric product, obtained inn yield, was a white fibrous solid having the following recurring structural units:

-I- C C-N N

The inherent viscosity of a polymer solution ~0.5 gram of the polymer of Example 14 per 100 mls. of a solution OX
five grams lithium chloride per 100 mls. of dimethylac_~àmlde) was 6.55 dl./gram at 30C. The molecular structure of Jo polymer was confirmed by infrared spectroscopy. the pox ye-I

was very slightly soluble in acetone, in tetrahydrofuran and in ethyl acetate and was soluble in amide-type solvents with or without added lithium chloride.
Elemental analysis for C36H18F12N2 2 P
following:
"C TAO OF I
Calculated: 58.23 2.44 30.71 3.77 4.85 Found: 57.87 2.50 30.56 3.77 5.3 (by difference) Thermogravimctric analysis showed that the onset of degradation of the polymer of Example 14 occurred at 4~GC in nitrogen and in air. Differential scanning calorimetry and thermal mechanical analysis of film samples detected a repro-educible transition at about 160C.
Polymeric films were pr~parcd prom the polymeric material of Example 13 by casting (onto glass plates) solutions of the polymeric material in a 5% wt./vol. solution of lithium chloride and dimethylacetamide (five grams lithium chloride per 100 mls. of dimethylacetamide)~ The concentration of polymer ranged from 0.5 to I Whitehall., isle from Grimm to five grams polymer per 100 mls. of the lithium chlor1de/dimethyl-acetamide solution. In each instance, the glass plate carrying the puddle-cast polymer solution was immersed in water wafter minimal evaporation of solvent). The polymer film was observed to gel and a transparent and colorless unwarranted film separated from the glass plate. The resulting film was soaked for several hours in water to effect extraction of occluded lithium chloride and solvent, soaked in acetone and dried ion a vacuum oven at 90C and 15 mm. pressure. Refractive index, measured by inter-formatter, was 1.79.

Stretched polymeric films were prepared in ho following manner. Water-swollen films (obtained by soaring ho polymer films for several hours for removal or occluded Lowe chloride and solvent as aforedescribed) were cut into strips.
The strips were mounted between the jaws of a mechanical unit directional stretcher. The Sty:; pus were stretched (in air at 220C) to effect film orientation. The stretched films were optically transparent. Birefringence, measured with the aid of a quartz wedge, was 0.293.
lo Solutions of the polymer of Example 14 in lithium chloride/dimethylacetamide, as aforedescribed, were formed into extruded films by the wet jet method whereby the soul-lion of polymer is eroded into an aqueous coagulation bath for golfing of the polymer material The resulting transparent colorless film strips were soaked in water and cut to about l to 2 inches (25.4 to 50.8 mm.) for testing. The partially oriented strips of film produced by the extrusion were further oriented by stretching in the manner described in the Examples hereof. Mcasurerncnt of birefringence utilizing a quartz wedge provided a birefringence value of 0.44.

Geometric indices were determined for the repeating Us s of polymeric materials having the following structure 11 r wherein each X is hydrogen or a substituent as set forth in the following 'Lubell I. In the case of each recurrincJ unit, i en the eccentricity factor l + e was calculated and is reported in TABLE I. Bond and group polarizability tensors were utilized to calculate a polarizabili~y matrix for each repeat unit, the diagonalized form of the matrix providing the X, Y and Z contributions to the us t polarizability ellipsoid. axial polarlzabilltles, i.e., X, Y and Z, wore utilized to calculate longitudinal and transverse eccentric-vies of each repeat unit, thus, reflecting its symmetry.
~ccer.~ricity values were calculated utilizing the following procedure. A polarizability and a corresponding orthogonal coordinate system is assigned to each segment of the polymer repeat unit. Literature values for group polarize lo abilities arc uti~izcd from the literature, or where not available, are constructed from bond polarizabilities.
Available Danube values were utilized herein or all cowlick-Lyons. Bond polarizabilities are utilized to connect segments where necessary. To determine the overall polarize ability of the repeat unit, the coordinate system of the segment at one end of the repeat unit is made coincident with that of the adjacent segment by means of the appropriate I .). rrh~ I I I ] I ah successive segmelit Whitehall the last segment is reached- Mathematically, this Lillian thaw the matrix ox ogle sogme~l~ must by pro- and post-multiplicd by a transformation matrix:
I= T us To where I is the polarizability of segment; T is the trays-formation matrix; T-l is the inverse of T; and I is the polarizability of segment 1 in the coordinate system of segment 2. The value of I is then added to I and the ~ralls~ormation repeated. Lowe repeat unit polarizability matrix is diagonalized, thus, providing a repeat unit polarizability ellipsoid with three semi-axes, i.e., ox yard ~zz, where ox is the major polarizabillty an is coincident with the polymer backbone.

AL

Literature-reported values of 25~ and 31, rcsiJec~
lively, were utilized in all calculations as representing the dihedral angle between the phenol and carbonyl moieties and the dihedral angle between the phenol and amino moieties, respectively. Expcrimcn~ally determined values for the dihcdr~l angle between each X-substituted phenol moiety were utilized in all calculations and are reported in TABLE I. Mean diameter values, D, and length, L, were obtained from space-filling molecular models.

TABLE I

Substituent X Diameter Length if + elm (Dihedral Angle) (D) J G

(20) 4.49 21.35 1.061 0.98g (60) 4.61 21.35 1.206 1.21 Of (72) 4.78 21.35 1.348 1.23 By (75~) 4.83 21.35 1.388 1.~4 (~5) 4.91 21.35 1.428 1.26 c~3 (80) 4.90 21.35 1.496 L.33 SHEA
(71) 4.76 21.35 1.330 1.25 From the data presented in TABLE I will be observed the influence of the nature of the X substituent relative to a hydrogen atom as regards the reported dihedral angle and ruling substantial non coplanarity between inter bonded l~hcnyl rinks. DiEEerenccs in mean diameter and influence of the nature of X substituents on mean diameter and eccentricity factor, and correspondingly, geometric index G will also be observed. Thus, it will be noted that the largest subs~ituell~s, ______~

i.e., -CF3 and I subs~ituents, corresponded with the lyrics dihedral angles between inter bonded phenol groups or the highest non-coplanari~y and, accordingly, recurrincJ unit having such substituents show hush geometric index values.
For purposes of comparison, geometric index G was alkaloid Jo. ho Roy Wilt of poly(p-phenylcrle)tere~ hat-nil avid ha ~ollowin~J structure and the rcsul~s thereof art reported in TABLE II. Dihedral angle values of 25 and 31 were utili~cd for purposes ox calculation as in the case of the arc us ox ~XAMl'LE 15.

N
31~
TABLE II
. .
Mean 1 + en DiameterLenc-th (Do (L) 1 + e G
T
4.43 12.45 0.978 0.621 As can be observed from inspection of the data reported in TABLES I and II, the geometric indices for the repeat units of the materials set forth in TABLE I are considerably higher than the geometric index calculated for Lyle yule ~r~lllLII~l~l~ AL Lyle 11.

Geometric indices for the recurring units of lulled llavisly ho hollowing structure were calcula~cd.
Each X substituent was as indicated in TABLE III. Dihedral angles From the literature were utilized in such calculation Calculated geometric indices were compared with values of oracle my inlum bircFri~lgcllcc for ho polymeric mocker rcuorted in TABLE III. Theoretical maximum birefringencc values (I Max) were obtained by plotting the orientation function, calculated from infrared dichroism, against experimental birefringence and extrapolating to 1004~
orientation. The results are set forth in TABLE III.

C~C C I Lowe on TALE III

Subs~itucnt X
(Dihedral Angle) G Max __ -By (75) 1.21 1.2Q

(80) 1.18 0.98 From the data presented in TABLE III, it will be seer.
that high values of geometric index G corresponded with high values of Max For purposes of comparison, the theoretical maxim birefrin~cnce value (I Max) for the recurring unit of poly~p-phenylene)terephthalamide (having a G value of 0.621 c, as shown in TABLE II) was also determined. The resulting nix value of 0.83 or poly(p-phenylene)terephthalamide was higher 1 h Jo l l Wow Us J r Lo L LX~III Lo J I: OWE: I; r i C i no I Via 0.621. This is believed to be the result of the highly crystalline nature ox the poly(p-phen~lene)terephthalamide nla~erial, whereas the geometric index G reflects the inherent an isotropy of an isolated chain independent ox such macro-scopic properties as morphology, density, color or the like.
The enhanced optical an isotropy exhibited by the preferred substituted-aromatic polyamide materials utilized in the optical devices hereof is believed to be the result of Lo wrecked, rod-like uniaxial molecular structure ox con knurls and the amorphous/crystalline ratio thereof. This ratio typically ranges from about 10:1 to about 20:1~ In the case of highly unidirectionally oriented phenyl-typei polyp asides this ratio generally will be on the range of about 0.3:1.
The presence of crystallizes is generally detrimental in polymeric materials adapted to utilization in optical devices owing to light scattering and diminished transparency.

The non-cc~planarity bc~wccin substituted biphenyl rings, resulting from starkly bulky groups on the ortho positions of inter bonded phenol zings, raises the amorphous/crystalline ratio to a range of about 10:1 to about 20:1. This permits the EaJ~rica~ion of haggle oriented films and gibers exhibiting high transparency in addition to high bireringence. The ring-substituted biphenyl polyamides additionally exhibit enhanced volubility and can be fabricated into colorless films or fibers where desired.

~XAMI'LE 17 Geometric indices were del~irmined lion the repeating units of polymeric materials having the following structure I

whcL-cein each X is hydroyon or a subs~i~uent as sex o'er hi followincJ TABLE IV. In Thea case of each recurrincJ unwell, 1 en ho eccentrically factor + e was calculated and it roof in lo IV. Bond and group polarizability tensor Wylie_ utilized to calculate a polarizabi~ matrix for ever 'Lotte unit, the diagonali~ed form of the matrix r the X, Y and Z contributions to the unit polarizabili~y ellipsoid. Axial polarizabilities, i.e., X, Y and z, were utilized to calculate longitudinal and transverse eccPntrici-ties of each repeat unit, thus, reflecting its Sinatra.
Eccentricity values were calculated utilizing the I urn Skye forth in Lowe 15.
Li!cra~urc-rcl~or~d valves of 25 and 31, rc~L~cc-lively, were utilized in all calculations as representing the dihedral angle between the phenol and carbonyl moieties and the dihedral ankle between the phenol and amino moieties, respect timely Experimentally determined values for the dihedral angle between each Substituted phenol moiety were utilized in all calculations and are reported in TABLE IV. Mean diameter values, D, and length, L, were obt~incd from space-filling molecular models.

TABLE IV
Mean Subs~ituc~ X Diameter Length I en (Dihedral Ankle) (I G
.___ _ (20) 4.52 29.80 0.938 1.373 I ~.66 29.80 1.155 1.640 ('12) 4.8~ 29.80 1.166 1.594 By (75) 4.90 29.80 1.145 1.5~6 (~5) 4.99 29.80 1.271 1.685 (owe) 4.98 29.80 10286 1.7 SHEA
(71) 4.82 29.8~ 1.181 1.6_~

prom the data presented in TABLE IV e observed the influence of the nature ox the X substituer~ Rowley dl-ocJen Allen as recJards the reported dihedral angle an -99~

.$

resulting subs~ntial non coplanarity between in~orbondcd phcnyl rowers. erences in mean diameter and influence of ho nature of X substituenls on moan diameter and eccen~rici~
favor, an correspondingly, geometric index G will also be observed. Thus, it will be noted aye the largest subs~i~uen-~, icky., -CF3 and -I substituents, corresponded with the largely dihedral angles between inter bonded phenol groups or the hicJhe~ non coplanarity and, accordingly, recurring units having such subs~ituen1-s show high geometric index values.

I :XAMl'LI. I
ht-polarizinc3 device utili~iny a highly birefringent polyamide material was constructed in the following manner.
Sue of birefrinyent material was prepared from the polyamide of example if, i.e., polyl2,2'-bis(trifluoro-methyl)-~,4'-biphenylene]-trans-p,p'-stilbene dicarboxamide.
The sheet was prepared by the "wet-jet" extrusion method described in example if. The resulting extruded polymer, in the form of a partially oriented transparent colorless film, was soaked in water and cut into strips. The strips were then further oriented by stretching in air in the manner also desk cried in Example if. A strip of the birefringent polymer (having perpendicular and parallel indices of refraction, respectively, of approximately 1.72 and 2.34 and an approximate thickness of 25 microns) was embossed by contacting one surface of the strip with a brass prismatic plate heated to a temperature of 180C and pressing the heated plate onto the surface of the film so as to provide a prismatic layer of birefringent material generally shown in Figure 6 as layer 42.
Onto a sheet of transparent isotropic glass material of approximately one-mm. thickness was poured a layer of polyp chlorinated biphenyl, an isotropic material having an index of refraction of 1.654, available as Aroclor 1260~ from Monsanto Company, St. Louis, Missouri. The prismatic layer of birefring-en material, prepared as aforesaid, was placed onto the layer of Aroclor. The prismatic layer was covered with a second layer of Aroclor so as to embed the prismatic layer in Aroclor mater-tat. A second sheet of glass was placed onto the Aroclor so as to sandwich the birefringent and Aroclor materials between the two pieces of glass. The resulting polarizer device was tested for its light polarizing properties by placing the test device and a second polarizer into the path of a light beam and by observing the attenuation of light resulting from rotation of the respective polarizers.

trade Mark 121~

This Example illustrates the preparation, in accord-arc with the reaction sequence set forth herein before, of 4,4"'-dinitro-2,2',3",2"'-tetrakis-(trifluoromethyyule":
~",l"'-quaterphenyl and the corresponding immune compound.
Part A. - Preoaratio~ of buster lùorumethYl)-4,4'-dinitro-l,l'-biphenyl To a solution of 2-bromo-5-nitro-benzotrifluoride l50 growers) in 100 mls. of dimethylformamide were added 45 grams of activated copper and the mixture was reflexed for five hours.
The reaction mixture was cooled and poured into excess water.
The product, a brown precipitate, was filtered off, washed with water and dried. Chromatography over silica gel provided the product 2,2'-bis-(trifluoromethyl)-4,4'-dinitro-1,1'-biphenyl which was recrystallized from ether as shiny yellow prisms exhibiting a melting point of 140C.
Part B. - Preparation of 4-amino-2,2'-bis-(trifluoromethvl)-, ` 4'-nitro-1,1'-biphenYl ;;~ In 50 mls. of methanol and 75 mls. o Tulane, 4.75 grams of the product from Part A were dissolved. The solution was reflexed while a solution (2.1 grams of sodium hydrosulfide in 50 mls. of water and 50 mls. of methanol) was added drops over a 45-minute period. As shown by thin layer chromatography, the reaction was completed 150 minutes after the addition. The reaction solvents were removed in vacua. Water (100 mls.) was added to the residue, and then extracted with ethyl acetate.
Jo Lola -~21~

The organic layers were washed with water, dried (assay) and solvent removed 'Jo provide a yellow syrup-like liquid. Thin layer chromatography showed a trace of the corresponding Damon compound in the resulting product which was utilized without purification in Part C as follows.
rewrote C - Preparation of 2.2'-bis-(trifluorome.hyl)-4-iodo-4'-nitro-1,1'-biphenyl The product from Part B (4.5 grams) was diazotized Whitehall sodium nitrite and hydrochloric acid and the diazonium salt solution was added slow' to a stirring solution of potassium iodide (5 grams), iodine (1 gram) and water (10 mls.) maintained at 0C. The temperature was allowed to r so to room temperature and the reaction mixture was stirred for one-half hour and then heated over a steam bath for one hour. The reaction mixture was cooled, diluted with water, excess iodine was destroyed by adding sodium bisulfite and extracted with ethyl acetate. The ethyl acetate layers were washed with aqueous sodium basalt and water, dried (Nazi) and vapor-axed to provide a yellow low-melting solid. This was absorbed on dry column silica gel. Elusion with benzene/hexane (l/2)g2ve 4.2 grams of 2,2'-bis-(trifluoromethyl)-4-iodo-4'-nitro-1,1'-biphenyl and 0.15 tram of the Dodd compound. The desired compound was crystallized as a pale yellow solid from methanol and exhibited a melting point of 67-68C.
Part D. - Preparation of 4,4i'--dinitro-2,2',3",2"'~tetrakis-. .
(tri~luoromethyl)-1,1':4',1":4",1"'-~_terphenAvl Nine grams Go the compound from Part C were dissolved in 20 mls. of dimethylformamide. Nine grams of activated copper were added and the reaction mixture was reflexed under nitrogen for 30 hours. The mixture was poured into water, the brown - loll -precipitate was filtered off, washed with waxer and dried. It was extracted overnight in a Sexuality extractor with acetone and the acetone solution was evaporated to provide a Yellow residue.
Chromatography over dry column silica gel and elm ion with benzene/hexane (1/1) guy a white solid, crystallized as short while needles from chloroEorm/methanol and exhibiting a melting pullout ox 250-255C.
Purity. - Preparation of 4,4"'-diamino-2,2',3",2"'-tetxakis-(trifluoromethyl)-1,1':4',1": 4 "_! a rphenyl The compound from Part D hereof (4 yams) was well minced with 11 grams of Snuck 2I~2O to which absolute ethanol (10 mls.) was added and stirred while concentrated hydrochloric acid (15 mls.) was dropped in carefully. The mixture was reflexed overnight, ethanol was removed, water was added to the residue and then made basic with guy sodium hydroxide. The white precipitate was filtered off, dried and extracted over-night in a Sexuality extractor with ethyl acetate. Removal of solvent and recryst~lli anion of the residue from chloroform/
hexane gave the desired Damon compound as short white needles exhibiting a melting point of 208-210~C.
I analysis fur Cliff 2 P
following I go % 'OWE

Ccllcul~t~: 55.3 2.6 4.6 37.5 Found: 55.4 2.7 4.637.4 - loll -

Claims (91)

What is claimed is:

1. An optical device including a transparent molecularly oriented highly birefringent polymer, said highly birefringent polymer comprising repeating molecular units exhibiting high electron density substantially cylindrically distributed about the long axes of the polymer and the repeating units thereof, said highly birefringent polymer being substan-tially optically uniaxial exhibiting only two indices of refraction.

2. The device of Claim 1 wherein the birefringence of said polymer is in relation to the molecular configuration of said repeating molecular units and tune cylindrical or ellip-soidal electron density distribution about said axes according to a dimensionless geometric index G represented by the relationship G = 0.222 x E x ?
wherein E is a dimensionless eccentricity factor defined by the relationship where eL is the longitudinal eccentricity of the electron polarizability of the repeating molecular unit and eT is the transverse eccentricity of the polarizability of the repeating molecular unit, L is the length of the repeating molecular unit along the main axis thereof and D is the mean diameter of the repeating molecular unit and wherein said geometric index G has a value of about 0.5 or higher.

3. The device of Claim 2 wherein said geometric index G has a value of one or higher.

4. The device of Claim 3 wherein said geometric index G has a value of 1.2 or higher.

5. The device of Claim 1 wherein said molecularly oriented highly bircfrincgent polymer has a birefringence of at least 0.2.

6. The device of Claim 5 wherein said molecularly oriented highly birefrinsent polymer has a birefringence of at least about 0.4.

7. The device of Claim 2 wherein said molecularly oriented highly birefringent polymer has a birefringence of at least about 0.2.

8. The device of Claim 7 wherein said molecularly oriented highly birefringent polymer has a birefringence of at least 0.4.

9. The device of Claim 1 wherein said molecularly oriented highly birefringent polymer is in the form of a uni-directionally stretched polymer layer.

10. The device of Claim 1 wherein said molecularly oriented highly birefringent polymer comprises recurring units of the formula -IMAGE-wherein each of A and B is a divalent radical except that B
can additionally represent a single bond; R and R1 are each hydrogen, alkyl, aryl, alkaryl or aralkyl; and c is zero or one; and wherein, when c is one, at least one of A and B is a divalent radical selected from the group consisting of:

(1) a radical -IMAGE-where U is a substituent other than hydrogen, each W is hydrogen or a substituent other than hydrogen, p is an integer from 1 to 3, each X is hydrogen or a substituent other than hydrogen and r is an integer from 1 to 4, said U, Wp and Xr substitution being sufficient to provide said radical with a non-coplanar molecular configuration; and -IMAGE-(2) a radical where each of Y and Z is hydrogen or a substituent other than hydrogen and each t is an integer from 1 to 4, with the proviso that when each said Z is hydrogen, at least one said Y substituent is a substituent other than hydrogen positioned on the corresponding nucleus ortho with respect to the ?= moiety of said radical, said and Yt substi-tution being sufficient to provide said radical with a non-coplanar molecular configuration;
and wherein, when c is zero, A is a divalent radical selected from the group consisting of radicals (1) and (2) as herein-before defined.

11. The device of Claim 10 wherein c of said recurring units is the integer one.

12. The device of Claim 11 wherein each of said A and B radicals of said recurring units is a divalent radical having the formula -IMAGE-wherein U is a substituent other than hydrogen, each W is hydrogen or a substituent other than hydrogen, p is an integer from 1 to 3, each X is hydrogen or a substituent other than hydrogen and r is an integer from 1 to 4, said U, Wp and Xr substitution being sufficient to provide said radicals with a non-coplanar molecular configuration.

13. The device of Claim 12 wherein each said A and radical is a divalent radical having the formula -IMAGE-wherein each of U and X is a substituent other than hydrogen.

14. The device of Claim 13 wherein each of said U
and X substituents is selected from the group consisting of halogen, nitro, alkoxy and substituted-alkyl.

15. The device of Claim 14 wherein each said U and X substituent is bromo.

16. The device of Claim 14 wherein each of said U
and X substituent is nitro.

17. The device of Claim 14 wherein each said U and X substituent is trifluoromethyl.

18. The device of Claim 12 wherein said divalent radical A is a radical having the formula -IMAGE-wherein p is the integer 3, r is the integer 4 and each of U, W and X is a substituent other than hydrogen.

19. The device of claim 18 wherein each said U, W and X substituent is halogen.

20. The device of claim 19 wherein each said U, w and X substituent is fluoro.

21. The device of Claim 12 wherein said divalent radical A is a radical having the formula wherein p is the integer 3, r is the integer 4 and each of U, W and X is a substituent other than hydrogen; and said divalent radical B is a radical having the formula wherein each of U and X is a substituent other than hydrogen.

22. The device of Claim 21 wherein, in said radical A having the formula where p is the integer 3 and r is the integer 4, each of said U, W and X substituents is fluoro, and wherein, in said radical B having the formula each said U and X substituent is bromo.

23. The device of Claim 11 wherein said divalent radical A is the radical having the formula ; and said divalent radical B is a radical having the formula wherein U is a substituent other than hydrogen, each W is hydrogen or a substituent other than hydrogen, p is an integer from 1 to 3, each X is hydrogen or a substituent other than hydrogen and r is an integer from 1 to 4, said U, Wp and Xr substitution being sufficient to provide said radical with a non-coplanar molecular configuration.

24. The device of Claim 23 wherein said divalent radical B is a radical having the formula wherein each of U and X is a substituent selected from the group consisting of halogen, nitro, alkoxy and substituted-alkyl.

25. The device of Claim 24 wherein each of said U
and X is halogen.

26. The device of Claim 24 wherein each of said U and X is bromo.

27. The device of Claim 24 wherein each of said U and X is trifluoromethyl.

28. The device of Claim 11 wherein said divalent radical A is a radical having the formula wherein each of U and X is a substituent other than hydrogen, and said divalent radical B is a radical having the formula -IMAGE-wherein U is a substituent other than hydrogen, each W is hydrogen or a substittuent other than hydroyen, p is an integer from 1 to 3, each X is hydroyen or a substituent other than hydrogen and r is an integer from 1 to 4, said U, Wp and Xr substitution being sufficient to provide said radical with a non-coplanar molecular configuration.

29. The device of Claim 28 wherein, in said radical A, each of said U and X substituents is halogen; and wherein, in said radical B, p is the integer one, r is the integer two and each X substituent is selected from the group consisting of haloyen, alkoxy and substituted-alkyl.

30. The device of Claim 29 wherein said radical B
is a radical having the formula -IMAGE-where W and X are each alkoxy,

31. The device of Claim 11 wherein said B represents a single bond and said divalent radical A is a radical having the formula -IMAGE-wherein U is a substituent other than hydrogen, each W is hydrogen or a substituent other than hydrogen, p is an integer from 1 to 3, each X is hydrogen or a substituent other than hydrogen and r is an integer from 1 to 4, said U, Wp and Xr substitution being sufficient to provide said radical with a non-coplanar molecular configuration.

32. The device of Claim 31 wherein said p is the integer 3, 4 is the integer 4 and each of U, W and X is halogen.

33. The device of Claim 31 wherein each said U, W and X is fluoro.

34. The device of Claim 11 wherein said divalent radical A is the radical having the formula -IMAGE- ; and said divalent radical B is a radical having the formula -IMAGE-wherein U is a substituent other than hydrogen, each W is hydrogen or a substituent other than hydrogen, p is an integer from 1 to 3, each X is hydrogen or a substituent other than hydrogen and r is an integer from 1 to 4, said U, Wp and Xr substitution being sufficient to provide said radical with a non-coplanar molecular configuration.

35. The device of Claim 34 wherein said divalent radical B is a radical having the formula -IMAGE-wherein each of U and X is a substituent selected from the group consisting of halogen, nitro, alkoxy and substituted-alkyl.

36. The device of Claim 35 wherein each of said U and X is halogen.

37. The device of Claim 36 wherein each of said U and X is bromo.

38. The device of Claim 35 wherein each of said U and X is trifluoromethyl.

39. The device of Claim 11 wherein said divalent radical A is the radical having the formula ; and said divalent radical B is a radical having the formula wherein U is a substituent other than hydrogen, each W is hydrogen or a substituent other than hydrogen, p is an integer from 1 to 3, each X is hydrogen or a substituent other than hydrogen and r is an integer from 1 to 4, said U, Wp and Xr substitution being sufficient to provide said radical with a non-coplanar molecular configuration.

40. The device of Claim 39 wherein said divalent radical B is a radical having the formula wherein each of U and X is a substituent selected from the group consisting of halogen, nitro, alkoxy and substituted-alkyl.

41. The device of Claim 40 wherein each of said U
and X is halogen.

42. The device of Claim 41 wherein each of said U and X is bromo.

43. The device of Claim 40 wherein each of said U
and X is trifluoromethyl.

44. The device of Claim 11 wherein each of said A
and B radicals is a divalent radical having the formula -IMAGE-where each of Y and Z is hydrogen or 3 substituent other than hydroqen and each t is an integer from 1 to 4, with the proviso that when each said Z is hydrogen, at least one said Y sub-stituent is a substituent other than hydrogen positioned on the corresponding nucleus ortho with respect to the ? moiety of said radical, said Z and Yt substitution being sufficient to provide said radical with a non-coplanar molecular configuration and a geometric index G of at least 1.0; and

45. The device of Claim 44 wherein, in each of said radicals A and B, each said Z is hydrogen, each said t is the integer one and each corresponding Y substituent is a substituent other than hydrogen position on the corresponding nucleus ortho with respect to the ? moiety of the radical.

46. The device of Claim 45 wherein each said Y
subsituent is selected from the group consisting of halogen, nitro and alkoxy.

47. The device of Claim 44 wherein, in each of said radicals A and B, each Y is hydrogen, each t is the integer four, one said Z is hydrogen and the remaining said Z substi-tuent is halogen.

48. The device of Claim 47 wherein said halogen is bromo.

49. The device of Claim 11 wherein said divalent radical A is a radical having the formula -IMAGE-where each of Y and Z is hydrogen or a substituent other than hydrogen and each t is an integer from 1 to 4, with the proviso that when each said Z is hydrogen, at least one said Y sub-stituent is a substituent other than hydrogan positioned on the corresponding nucleus ortho with respect to the ? moiety of said radical, said Z and Yt substitution being sufficient to provide said radical with a non-coplanar molecular configuration; and wherein said divalent radical B is a radical having the formula -IMAGE-wherein U is a substituent other than hydrogen, each W is hydrogen or a substituent other than hydrogen, p is an integer from 1 to 3, each X is hydrogen or a substituent other than hydrogen and r is an integer from 1 to 4, said U, Wp and Xr substitution being sufficient to provide said radical with a non-coplanar molecular configuration.

50. The device of Claim 49 wherein, in said radical A, each said t is the integer four, each corresponding Y is hydrogen, one said Z is hydrogen and the remaining said Z is halogen.

51. The device of Claim 50 wherein said halogen is bromo.

2. The device of Claim 50 wherein said radical B
is a radical having the formula -IMAGE-wherein each of U and X is a substituent selected from the group consisting of halogen, nitro, alkoxy and substituted-alkyl.

53. The device or Claim 52 wherein each of U and X
is halogen.

54. The device of Claim 53 wherein each halogen is bromo.

55. The device of Claim 10 wherein c is zero and said divalent radical A is a radical selected from the group consisting of:

(1) a radical -IMAGE-where U is a substituent other than hydrogen, each W is hydrogen or a substituent other than hydrogen, p is an integer from 1 to 3, each X is hydrogen or a substituent other than hydrogen and r is an integer from 1 to 4, said U, Wp and Xr substitution being sufficient to provide said radical with a non-coplanar molecular configuration; and -IMAGE-(2) a radical where each of Y and Z is hydrogen or a subscituent other than hydrogen and each t is an integer from 1 to 4, with the proviso that when each said Z is hydrogen, at least one said Y substit-uent is a substituent other than hydrogen positioned on the corresponding nucleus ortho with respect to the ? moiety of said radical, said Z and Yt substitution being sufficient to provide said radical with a non-coplanar molecular configuration.

56. The device of Claim 55 wherein said divalent radical A
is a radical having the formula -IMAGE-wherein U is a substituent other than hydrogen, each W is hydrogen or a substituent other than hydrogen, p is an integer from 1 to 3, each X is hydrogen or a substituent other than hydrogen and r is an integer from 1 to 4, said U, Wp and Xr substitution being sufficient to provide said radical with a non-coplanar molecular configuration.

57. The device of Claim 55 wherein said divalent radical is a radical having the formula -IMAGE-wherein each of U and X is a substituent other than hydrogen.

58. The device of Claim 57 wherein each of said U and X
substituents is selected from the group consisting of halogen, nitro, alkoxy and trifluoromethyl.

59. The device of Claim 58 wherein each said U
and X substituent is bromo.

60. The device of Claim 58 wherein each said U and X substituent is nitro.

61. The device of Claim 55 wherein said divalent radical A is a radical having the formula -IMAGE-where each of Y and Z is hydrogen or substituent other than hydrogen and each t is an integer from 1 to 4, with the proviso that when each said Z is hydrogen, at least one said Y sub-stituent is a substituent other than hydrogen positioned on the corresponding nucleus ortho with respect to the ? moity of said radical, said and Yt substitution being sufficient to provide said radical with a non-coplanar molecu-lar configuration.

62. The device of Claim 61 wherein, in each of said radicals A and B, each said Z is hydrogen, each said t is the integer one and each corresponding Y substituent is a substituent other than hydrogen position on the corresponding nucleus ortho with respect to the ? moiety of the radical.

63. The device of Claim 62 wherein each said Y
substituent is selected from the group consisting of halogen, nitro and alkoxy.

64. The device of Claim 61 wherein, in each of said radicals A and B, each Y is hydrogen, each t is the integer four, one said Z is hydrogen and the remaining said Z substituent is halogen.

65. The device of Claim 64 wherein said halogen is bromo.

66. The device of Claim 11 wherein said divalent radical A is the radical having the formula -IMAGE- ; and said divalent radical B is a subsbituted-quaterphenylene radical having the formula -IMAGE-wherein each U is a substituent other than hydrogen, each W is hydrogen or a substituent other than hydrogen, each p is an integer from 1 to 3, each X is hydrogen or a substituent other.
than hydrogen and each r is an integer from 1 to 4, said U, Wp and Xr substitution being sufficient to provide said radical with a non-coplanar molecular cofiguration.

67. The device of Claim 66 wherein said divalent radical B is a substituted-quaterphenylene radical having the formula -IMAGE-wherein each of U and X is a substituent selected from the group consisting of halogen, nitro, alkoxy and trifluoromethyl.

68. The device of Claim 67 wherein each of said U
and x substituents is trifluoromethyl.

69. The device of Claim 11 wherein said divalent radical A is the radical having the formula -IMAGE- ; and said divalent radical B is a substitued quaterphenylene radical having the formula -IMAGE-wherein each U is a substituent other than hydrogen, each W
is hydrogen or a substituent other than hydrogen, each p is an integer from 1 to 3, each X is hydrogen or a substituent other than hydrogen and each r is an integer from 1 to 4, said U, Wp and Xr substitution being sufficient to provide said radical with a non-coplanar molecular configuration.

70. The device of Claim 69 wherein said divalent radical B is a substituted-quaterphenylene radical having the formula -IMAGE-wherein each of U and X is a substituent selected from the group consisting of halogen, nitro, alkoxy and trifluoromethyl.

71. The device of Claim 70 wherein each of said U
and X substituents is trifluoromethyl.

72. A multilayer light-transmitting device comprising, in assembled bonded relation. a layer of transparent molecularly oriented highly birefringent polymer comprising repeating molecular units exhibiting high electron density substantially cylindrically distributed about the long axes of the polymer material and the repeating units thereof, said highly birefrin-gent polymer exhibiting a birefringence in relation to the molecular configuration of said repeating molecular units and the cylindrical or ellipsoidal electron density distribution about said axes, said birefringence being in relation to said molecular configuration and said electron density distribution according to a diminsionless geometric index G represented by the relationship G=0.222 x E x LD wherein E is a dimensionless eccentricity factor defined by the relationship -IMAGE-where eL is the longitudinal eccentricity of the electron polar-izability of the repeating molecular unit and eT is the trans-verse eccentricity of the polarizability of the repeating molecular unit, L is the length of the repeating molecular unit along the main axis thereof and D is the mean diameter of the repeating molecular unit; said repeating molecular units of said birefringent polymer exhibiting a geometric index G of about 0.5 or higher; said multilayer light-transmitting device in-cluding at least one additional transparent layer having an index of refraction substantially matching one index of refrac-tion of said layer of transparent molecularly orlented highly birefringent polymeric material and comprising isotropic or birefringent material; said at least one additional transparent layer, when a layer of birefringent material, having one index of refraction thereof substantially different from one index of refraction of said layer of transparent molecularly oriented highly birefringent polymer and having a molecular orientation substantially perpendicular to the molecular orientation of said molecularly oriented highly birefringent polymer.

73. The multilayer light-transmitting device of Claim 72 wherein the repeating molecular units of said birefringent polymer exhibit a geometric index G of one or higher.

74. The multilayer light-transmitting device of Claim 72 wherein said layer of transparent molecularly oriented highly birefringent polymer is bonded to a trans-parent layer having an index of refraction suhstantially matching one index of refraction of said transparent molecu-larly oriented highly bircfringent polymer.

75. The multilayer light-transmitting device of Claim 72 wherein said layer of transparent molecularly oriented highly birefringent polymer is bonded between two transparent layers, one transparent layer having an index of refraction substantially matching the lower index of refrac-tion of said transparent molecularly oriented highly birefringent polymer.

76. The multilayer light-transmittiny device of Claim 75 wherein one of said two transparent layers has an index of refraction substantially matching the lower index of refraction of said transparent molecularly oriented highly birefringent polymeric material and the second of said two transparent layers has an index of refraction substantially matching the higher index of refraction of said transparent molecularly oriented highly birefringent polymer.

77. The multilayer light-transmitting device of Claim 72 comprising an alternating arrangement of a plurality of layers of said molecularly oriented highly birefringent polymer and a plurality of said additional transparent layers, each said additional transparent layer having an index of refraction substantially matching one of the two indices of refraction of each said layer of said molecularly oriented highly birefringent polymer.

78. The multilayer device of Claim 77 wherein each said additional transparent layer is isotropic.

79. The multilayer device of Claim 72 wherein said molecularly oriented highly birefringent polymer comprises recurring units of the formula -IMAGE-wherein each of A and B is a dlvalent radical except that B
can additionally represent a single bond; R and R1 are each hydrogen, alkyl, aryl, alkaryl or aralkyl; and c is zero of one; and wherein, when c is one, at least one of A and B is divalent radical selected from the group consisting of:

(1) a radical -IMAGE-where U is a substituent other than hydrogen, each W is hydrogen or a substituent other than hydrogen, p is an integer from 1 to 3, each x is hydrogen or a substitutent other than hydrogen and r is an integer from 1 to 4, said U, wp and Xr substitution being sufficient to provide said radical with a non-coplanar molecular configuratlon;and -IMAGE-(2) a radical where each of Y and Z is hydrogen or a substituent other than hydrogen and each t is an integer from 1 to 4, with the proviso that when each said Z is hydrogen, at least one said Y substi-tuent is a substituent other than hydrogen positioned on the corresponding nucleus ortho with respect to the ? moiety of said radical, said Z and Yt substitution being sufficient to provide said radical with a non-coplanar molecular configuration;

and wherein, when c is zero, is a divalent radical selected from the group consisting of radicals (1) and (2) as herein-before defined.

80. The multilayer device of Claim 72 wherein c of said recurring units is the integer one.

81. The multilayer device of Claim 79 wherein said divalent radical A is a radical having the formula -IMAGE-wherein each of U and X is a substituent other than hydrogen, and said divalent radical B is a radical having the formula -IMAGE-wherein U is a substituent other than hydrogen, each W is hydrogen or substutuent other than hydrogen, p is an integer from 1 to 3, each X is hydrogen or a substituent other than hydrogen and r is an integer from 1 to 4, said U,; Wp and Xr substitution being sufficient to provide said radical with a non-coplanar molecular configuration.

82. The multilayer device of Claim 81 wherein, in said radical A, each of said U and X substituents is halogen;
and wherein, in said radical B, p is the integer one, r is the integer two and each X substituent is selected from the group consisting of halogen, alkoxy and substituted-alkyl.

83. The multilayer device of Claim 82 wherein each said X substituent is trifluoromethyl.

84. The multilayer device of Claim 79 wherein said divalent radical A is the radical having the formula ; and said divalent radical B is a substituted-quaterphenylene radical having the formula wherein each U is a substituent other than hydrogen, each W is hydrogen or a substituent other than hydrogen, each p is an integer from 1 to 3, each X is hydrogen or a substituent other than hydrogen and each r is an integer from 1 to 4, said U, Wp and Xr substitution being sufficient to provide said radical with a non-coplanar molecular configuration.

85. The multilayer device of Claim 84 wherein said divalent radical B is a substituted-quaterphenylene radical having the formula wherein each of U and X is a substituent selected from the group consisting of halogen, nitro, alkoxy and trifluoromethyl.

86. The multilayer device of Claim 85 wherein each of said U and X substituents is trifluoromethyl.

87. The multilayer device of Claim 79 wherein said divalent radical A is the radical having the formula ; and said divalent radical B is a substituted-quaterphenylene radical having the formula -IMAGE-wherein each U is a substituent other than hydrogen each W is hydrogen or a substituent other than hydrogen each p is an integer from 1 to 3, each X is hydrogen or a substituent other than hydrogen and each r is an integer from 1 to 4, said U, Wp and Xr substitution being sufficient to provide said radical with a non-coplanar molecular configuration.

88. The multilayer device of Claim 87 wherein said divalent radical B is a substituted-quaterphenylene radical having the formula -IMAGE-wherein each of U and X is a substituent selected from the group consisting of halogen nitro, alkoxy and trifluoromethyl.

89. The multilayer device of Claim 84 wherein each of said U and X substituents is trifluoromethyl.

90. The multilayer device of Claim 72 wherein said molecularly oriented highly birefringent polymer exhibits a birefringence of at least about 0.2.

91. The multilayer device of Claim 90 wherein said molecularly oriented highly birefringent polymer exhibits a birefringence of at least 0.4.