OPTICAL ANISOTROPY OF A PHOTOREACTED SIDE-CHAIN LIQUID-CRYSTALLINE POLYMER-INDUCED BY LINEARLY POLARIZED UV-LIGHT

Linearly polarized (LP) UV photoreaction of a photo-crosslinkable side chain liquid-crystalline polymer (SLCP) containing photoreactive cinna moyl and biphenyl mesogenic groups (1) was studied. The optical anisot ropy of the polymer film was induced by the LP-UV photoreaction and wa s investigated by the temperature-controlled polarized UV absorption s pectroscopy and polarized FT-IR measurements. The reorientation of the nonreacted mesogenic groups along to the (E) over cap direction of th e incident LP-UV light during the photoreaction occurred at the LC tem perature range of the polymer, and the induced birefringence Delta n w as about 0.02. Because of the high-density photo-crosslinking, the LP- UV photoreacted film showed orientational stability up to 160 degrees C. (C) 1998 John Wiley & Sons, Inc.