First hyperpolarizabilities of dipolar photoconductive chromophores: an approach toward monolithic molecular materials for photorefractivity

Second-order optical nonlinearities of a series of dipolar photoconductive chromophores have been investigated by semiempirical quantum chemical calculations using time-dependent Hartree–Fock formalism in conjunction with PM3 parameter and experimental evaluation of the first molecular hyperpolarizability ( β ). A linear correlation between the measured and calculated β values was observed, and the structure–property relationship discussed in terms of the structural variation. It was noted that the optical nonlinearities of the dipolar photoconductive molecules with carbazole, indole, or indoline as donor units are large enough for the electrooptic and photorefractive applications.