LANGMUIR-BLODGETT-FILMS OF PHOTOCHROMIC POLYGLUTAMATES .5. MIXTURES OF A PHOTOCHROMIC POLYGLUTAMATE AND A LOW-MOLECULAR-WEIGHT AZO-DYE

In order to enhance the content of photoisomerizable chromophores in monolayers of the ''hairy rod'' like poly[5-(4-phenylazobenzyl) L-glutamate-co-5-[4-(hexadecyloxy)benzyl] L-glutamate], [4-hexyloxy(phenyl]azobenzene was admixed. For the low molecular weight dye in the E form, miscibility was found up to a content of three dye molecules per polymeric chromophore, by recording F/A isotherms for different compositions. The influence of the dye is more pronounced in the case of the polymeric chromophore in the E form, suggesting interactions between the different azobenzene moieties. The monolayers can be transferred to Langmuir-Blodgett (LB) film. The UV-vis spectroscopic results on these films also reveal enhanced interactions if both mixing partners are in the E form. Furthermore, structural changes upon irradiation could be detected within the LB films. Despite the interactions between the azobenzene moieties, there are segregation phenomena impeding the use of the mixed LB films in optoelectronical applications.