Synthesis, photoisomerization and thermo-optic property of azo optically active polymer

摘要

A novel azobenzene optically polymer (P-DA) was synthesized based on the azo chromophore molecule, chiral reagent L(-)-tartaric acid, acryloyl chloride and methacrylate. The P-DA was characterized by FT-IR, UV-Vis spectroscopy, !H NMR, DSC and TGA. The P-DA had high thermal stability up to its glass-transition temperature (Tg) of 110 ℃ and 5 % heat weight loss temperature of 199 °C. The UV-induced trans/cis photoisomerization and reflex-isomerization behaviors were investigated. The results indicated that the P-DA solution could undergo photochromism after irradiated by 365 nm UV light. The optical parameters: refractive index (n), the dielectric constant (ε) and thermal volume expansion coefficient (β) of P-DA were obtained. The thermo-optic coefficients are one order of magnitude larger than those of the inorganic materials, such as SiO_2 (l.lx10f~(-5) ℃~(-1) and LiNbO_3(4×10~(-5)℃~(-1)) and was larger than the organic material such as polystyrene (-1.23×10~(-4) ℃~(-1)) and PMMA (-1.20×10~(-4)℃~(-1)). The conclusion had a little significance to develop optical communication.