<title>Improved optical nonlinearity of poled phenylhydrazone-doped polymer films</title>

Abstract

The optical properties of two kinds of corona poled polymer films, NDA (4'-nitrobenzal-4-N,N-dimethylaniline) and a newly synthesized CNDA ((alpha) '-cyano-4'-nitrobenzal- 4-N,N-dimethylaniline) doped PMMA (polymethyl methacrylate) films were investigated with in situ second-harmonic generation (SHG) measurement and UV-Visible absorption measurement. Optimum corona poling temperatures of the polymer films were found to be lower than glass transition temperatures of the materials. Under the optimum corona poling condition, the second-order nonlinear susceptibility (chi) <SUP>(2</SUP>) of CNDA/PMMA is larger than that of NDA/PMMA. The molecular second-order polarizability (beta) of the CNDA was estimated to be about 146 X 10<SUP>-30</SUP> esu from the measured absorbance and (chi) <SUP>(2</SUP>). The relaxation of SHG intensity of CNDA/PMMA was slower than that of NDA/PMMA. We concluded that CNDA is a better dopant than NDA as a second- order nonlinear-optical material.