Studies on liquid crystalline and optical response behavior of poly[omega-(4 '-methoxy-4-azophenyloxy)hexyl]methacrylate

Side-chain polymer liquid crystals poly[omega-(4' -methoxy-4-azophenyloxy)h exyl] methacrylate (PMAAZO6) was synthesized by the reaction of potassium m ethacrylate and 4-methoxy-4' -(1-bromohexyloxy) azobenzene, then free radic al polymerization in THF, The polymer obtained was characterized by GPC , N MR , UV spectra , DSC and optical polarizing microscope, A typical Schliere n texture was observed. The DSC results showed that T-g, of the polymer obt ained was 61 degrees C, the phase trasition from smectic to nematic phase o ccurred at 91 degrees C, and isotropic temerature was 131 degrees C, The fi lm with 2 mu m thickness was obtained by casting the polymer solution in TH F on the dean glass plate. The photoresponsive behavior of the film obtaine d was examined under different conditions. The UV writing light with lambda =366 nm induced phase transition at temperature from room to isotropic temp erature. The responsive rate increased as the temperature increased. When p olarizing light with lambda>400 nm was used as writing light, the mesogenic unit was reoriented consistently by the mechanism of cis to trans transfor mation , and an ordered domain was formed only below T-g, of the polymer , because thermal movement of the polymer segments distroyed the ordered arra ngement at the temperatures higher than T-g.