AbstractThe anisotropy induced in a series of methacrylate polymers doped with Disperse Orange 3 (DO3, NO2-phenyl-N=N-phenyl-NH2) was investigated by polarized FTIR spectroscopy. Three kinds of methacrylate polymers with different glass transition temperature (Tg), poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), and poly(butyl methacrylate) (PBMA), were used as polymer matrices. Observed infrared absorption bands of DO3 in the polymer films were assigned to symmetric (NO2s) and antisymmetric (NO2as) stretching modes of NO2, and the C-N stretching mode of C-NH2 (C-N). The infrared dichroism was observed in these bands under the irradiation. The orientation factors, Kzfn, (f=x, y, z, n=trans, cis), for both isomers of DO3 were determined in the photostationary stite for every polymer matrix. The factors indicate that it is difficult for NO2 group to move in the PMMA during trans-cis-trans isomerization and that it is difficult for NH2 group to move in the PBMA. The dynamical behavior of DO3 molecules which depends on the kind of polymers could be interpreted from orientation factors. This study shows that polarized FTIR spectroscopy is one of the most powerful methods available to analyze the physical mechanisms of photoinduced anisotropy.
Single-crystal polarized FTIR spectroscopy and neutron diffraction refinement of cancrinite