HYPER-RAYLEIGH SCATTERING OF THIOPHENE-INCORPORATED POLYENE CHROMOPHORES WITH PI-CONFIGURATION LOCKING

The hyper-Rayleigh scattering (HRS) technique is used to determine and compare the first hyperpolarizabilities (beta) of thiophene-incorpora ted polyene chromophores with and without a configuration locked trans -triene bridge, To ensure the purity of the HRS signal, special attent ion is paid to its dependence on the fundamental intensity and the spe ctral content of the scattered radiation including the two-photon abso rption induced fluorescence. From the HRS results, it is found that th e configuration-locked trans-triene bridge enhances the beta values of the chromophores studied, The beta-enhancement is more pronounced whe n the electron acceptor CHC(CN)(2) in the chromophores is replaced wit h C-2(CN)(3). (C) 1997 Elsevier Science B.V.