Process for inducing alignment of liquid crystals and liquid crystal optical elements

A process for inducing alignment of a liquid crystal medium adjacent to a surface of an optical alignment layer comprising:

• (a) exposing at least one optical alignment layer to polarized light;
• the polarized light having a wavelength within the absorption band of said optical alignment layer;
• wherein the exposed alignment layer induces alignment of the liquid crystal medium at an angle + and -.theta. with respect to the direction of the polarization of the incident light beam and along the surface of the optical alignment layer;
• and
• (b) applying a liquid crystal medium to the optical alignment layer, wherein the optical alignment layer is a polyimide of structure I ##STR11## comprising the reaction product of at least one tetracarboxylic dianhydride and an amine component, wherein the amine component comprises a 2-substituted 1,4-benzenediamine wherein the 2-substituent X.sub.1 is an electron withdrawing group having a positive .sigma., and M is a tetravalent organic radical derived from said tetracarboxylic dianhydride containing at least two carbon atoms, no more than two carbonyl groups of the dianhydride being attached to any one carbon atom of the tetravalent radical.