Nonlinear optical materials: Synthesis, characterizations, thermal stability and electro-optical properties

Two series of thermal stable polyimides and polyimide/silica hybrid materials have been synthesized. The silica content in the hybrid materials was varied from 0 to 22.5 wt.% and SiO2 phase was well dispersed in the polymer matrix. The glass transition temperature (Tg) and the decomposition temperature (Td) were in the range 226–382 °C and 345–499 °C, respectively, for materials. The polymer solutions could be spin coated on the indium–tin–oxide (ITO) glass or other substrates to form optical quality thin films. The electro-optic coefficients (γ33) at the wavelength of 832 nm for polymer thin films poled were in the range of 12–25 pm/V and the values remained well (retained > 85% for more than 100 h). The heat capacities of some materials were in the range of 0.9755–1.1821 J K− 1 g− 1 for the temperature 273 and 363 K. No thermal anomaly was found in this temperature range. Most of them showed high thermal stability.