The synthesis and optical properties of novel fluorinated polyimides incorporated with highly electro-optic active thiazole and benzothiazole based chromophores

摘要

Novel, non-linear optical fluorinated polyimides were prepared by the Mitsunobu reaction of hydroxyl-containing hetarylazo chromophores with hydroxyl polyimides. Their structures were verified by FT-IR, ~1H NMR, UV-Vis spectra, elemental analysis and gel permeation chromatography. The resulting amorphous polyimides exhibited good solubility and can be easily spin-coated into thin films with good optical quality. The high electro-optic coefficients (r_(33)) obtained for the films of poled polyimides were attributed to the introduction of hetarylazo chromophores with large hyperpolarizability within the polyimides. The polyimides possess high glass transition temperature (201-210 °C) and therefore showed excellent temporal stability, retaining 88% of their initial non-linear optical response at 110 °C for >200 h. Low optical losses in the range of 1.9-2.3 dB cm~(-1) at 1550 nm were observed for the polyimides and the values of thermooptic coefficients ranged from -1.680 x 10~(-4) to -2.008 x 10~(-4)/°C.