THEORETICAL-MODEL OF PHOTOINDUCED ANISOTROPY IN LIQUID-CRYSTALLINE AZOBENZENE SIDE-CHAIN POLYESTERS

A theoretical framework for the temporal behavior of photoinduced anis otropy in liquid-crystalline azobenzene side-chain polyesters is const ructed. The domain structure of the material is taken into account and inter molecular interactions are included through a mean-field descri ption. Photoinduced trans <-> cis isomerization is taken as the domina ting source of chromophore reorientation events, and it is demonstrate d how this mechanism in conjunction with the multidomain picture is ab le to account for the long-term stability of the anisotropy. The photo induced birefringence is calculated by means of a truncated basis meth od, and in addition the photostationary solution is obtained. Comparis on between theory and experiment shows excellent agreement in the enti re range of intensities used experimentally. (C) 1998 Optical Society of America [S0740-3224(98)04203-9].