Synthesis and electro-optic properties of novel Y-type polyimide containing nitrothiazolylazodioxyphenyl group

摘要： New Y-type polyimide (5) containing nitrothiazolylazodioxyphenyl groups as nonlinear optical (NLO) chromophores, which are components of the polymer backbone, was prepared and characterized. Polyimide 5 is soluble in common organic solvents such as N,N-dimethylformamide and dimethylsulfoxide. Polyimide 5 shows a thermal stability up to 300 °C in thermogravimetric analysis with glass-transition temperature (Tg) obtained from differential scanning calorimetry near 130 °C. The second harmonic generation (SHG) coefficient (d33) of poled polymer film at the 1064 nm fundamental wavelength is around 2.32 pm/V. The dipole alignment of polymer 5 exhibits a thermal stability even at 5 °C higher than Tg, and there is no SHG decay below 135 °C due to the partial main-chain character of polymer structure, which is acceptable for NLO device applications.