PHOTOASSISTED POLING OF POLYMER MATERIALS STUDIED BY STARK SPECTROSCOPY (ELECTROABSORPTION) TECHNIQUE

Photoassisted poling of two polymer systems (i) a dilute solution of p'-diethylamino-p'-nitroazobenzene polycarbonate and (ii) the side chain copolymer poly[(ethylene)-co-(N-hexyl-N-(4-methacryloxy-butyl)-4-amino-4'-nitrostilbene)] was investigated. The poling was carried out at room temperature by a do electric field under simultaneous irradiation of the samples with nonpolarized light absorbed by the azobenzene and stilbene chromophores. The long memory polar order parameter is shown to be of the order of 0.07 and 0.0023, respectively for the two chromophores mentioned. The higher value for the azobenzene moiety, comparable to the value calculated from the Boltzmann distribution of excited dipoles in the same electric field, has been attributed to a higher probability of its trans-cis isomerization.