Synthesis and polarized light-induced birefringence of new polymethacrylates containing carbazolyl and azobenzene pendant groups

Low T-g copolymers of [11(N-carbazolyl)undecylmethacrylate] and [2,5-dimeth ylphenyl-[(4-nitrophenyl)azo] -phenoxyalkylmethacrylate] have been synthesi zed and the polarized light-induced birefringence of thick films (70 mu m) has been investigated at a constant deducted temperature relative to T-g(T - T-g = 10 degrees C). The optical properties of these copolymers have been studied in relation to the ate-dye content and the length of the alkyl spa cer between the ate-dye and the methacrylic backbone. They have been compar ed with the dispersion of (4-methoxy-2,5-dimethylphenyl)-(4-nitrophenyl)dia zene (DMNPAA) within a poly[11(N-carbazolyl)undecyl-methacrylate] and a pol y[N-vinylcarbazole] (PVK) matrix. The experimental. curves have been fitted by biexponentials, so emphasizing the effects of the copolymer structure o n the kinetics of the writing process. The photoinduced orientation is more than three orders of magnitude higher in a grafted material compared to th e dispersion version. The azo-dye concentration also has an important role in both the amplitude and the dynamics of the photo-orientation. (C) 2000 J ohn Wiley & Sons, inc.