Journal of Polymer Science Part A: Polymer Chemistry, Vol.38, No.12, 2245-2253, 2000
Novel polyesters with amino-sulfone azobenzene chromophores in the main chain
The synthesis and optical properties of a series of amorphous polyesters with amino-sulfone azobenzene chromophores in the main chain are presented. The condensation of alkyl diacid chlorides with 4-[(2-hydroxyethyl)ethylamino]-4'-(2-hydroxyethylsulfonyl)azobenzene (7) gave polymers that showed low and unstable photoinduced birefringence because of their low glass-transition temperature. The condensation of 7 with mixtures of adipoyl chloride and terephthaloyl chloride gave a polymer with a higher glass-transition temperature and a stable reversible photoinduced birefringence. A photostationary birefringence of 0.07 was observed. Surface profile gratings were optically inscribed and produced diffraction efficiencies less than or equal to 19%. Photostationary, long-term stable birefringence and surface-grating efficiency increased with polymer rigidity.
Keywords:azobenzene polymers;synthesis;main-chain chromophore bonding;photoinduced birefringence;surface-grating inscription;optical stability versus structure