PHOTOCHROMIC BEHAVIOR OF THIN-FILMS OF POLYMETHACRYLATE SUBSTITUTED WITH LATERALLY ATTACHED AZOBENZENES DISPLAYING LIQUID-CRYSTAL ALIGNMENTPHOTOCONTROL

Photo- and thermal isomerization of poly[2-(2-methacryloyoxy)azobenzen e] derivatives was investigated both in solution and in film state. In the photo-induced trans-cis isomerization, the rate in film state was smaller than that in solution. The kinetics of the thermal back react ion was proved to depend on the copolymerization ratio of the polymer. Linearly polarized light (LPL) irradiation of a thin film of the poly mer induced dichroism of the film. The degree of the dichroism was rel ated to the Tg of the polymers. In-plane alignment of nematic liquid c rystals (LCs) was regulated by photodichroic thin films. Heat treatmen t of a film before irradiation was a important factor for the photoreg ulation.