MEAN-FIELD THEORY OF PHOTOINDUCED MOLECULAR-REORIENTATION IN AZOBENZENE LIQUID-CRYSTALLINE SIDE-CHAIN POLYMERS

A novel mean-field theory of photoinduced reorientation and optical an isotropy in liquid crystalline side-chain polymers is presented and co mpared with experiments, The reorientation mechanism is based on photo induced trans <-> cis isomerization and a multidomain model of the mat erial is introduced. The theory provides an explanation for the high l ong-term stability of the photoinduced anisotropy as well as a theoret ical prediction of the temporal behavior of photoinduced birefringence . The theoretical results agree favorably with measurements in the ent ire range of writing intensities used experimentally.