Optical poling and its application in optical storage of a polyimide film with high glass transition temperature

The temperature dependence of optical poling of a side-chain azobenzene-polyimide film with high glass transition temperature was experimentally investigated. With the increase of the sample temperature the light-induced second-harmonic generation increased first, and then decreased as the temperature was near its glass transition temperature. The light-induced second-order nonlinear optical coefficient d(33) for the optimum temperature was determined to be 6.9 pm/V, which was about 2.7 times that obtained at room temperature. Compared with optical poling at room temperature, this thermal-assisted optical poling not only enhanced d(33) Of the polyimide film, but also improved the polar order stability of molecules. Optical storage based on optical poling was also demonstrated experimentally. (C) 1998 American Institute of Physics.