EFFECTS OF 2-PHOTON FLUORESCENCE AND POLYMERIZATION ON THE FIRST HYPERPOLARIZABILITY OF AN AZOBENZENE DYE

The technique of hyper-Rayleigh scattering (HRS) has been employed to investigate the first hyperpolarizability (beta) of the azo dye Disper se Red 19 and a polymer in which Disperse Red 19 appears as a side-cha in moiety. In addition to HRS, these two molecules were found to exhib it substantial two-photon-induced fluorescence (TPF). The TPF spectra for these molecules were measured, and corrected HRS intensities were obtained. Using an external reference method, beta values of (1480 +/- 100) x 10(-30) and (1470 +/- 90) x 10(-30) esu were determined for th e dye and polymer systems, respectively, in dimethyl sulfoxide at 1064 nm. The difference between these two values is very small and shows t hat the effect of polymerization on the HRS intensity, in the dilute c oncentration limit, is negligible.