Electrochromic mechanism study of corona poled electro-optic polymer films

In the study of electro-optic polymer with nonlinear optical activity the phenomena of electrochromic shifts and intensity decreases of charge-transfer absorption bands in the polymer film after corona poling have been used to real-time monitoring of the corona-poling process and poling stability. However, the reasons of producing these phenomena are studied very little. In this paper the structure changes of the chromophore dipoles doped or chemically attachment to polymer macromolecules before and after poling were investigated by means of the measuring of UV-VIS and IR spectra. The electrochromic mechanism was discussed. The results indicated that the main reason of electrochromic shifts was the deformation of the conjugate pi system in the chromophore dipole. The used solvent when the specimen were prepared will affect material structure.