The synthesis and nonlinear optical property of carbazole-azo binary compounds

A series of novel carbazole-azo binary compounds was synthesized by modifying 9H-carbazole. The permanent dipole moments of their ground states were estimated by Fishtine method. A simple way generated from solvatochromic method was successful to calculate their first hyperpolarizabilities in the order of 10 −28 esu, which are comparable with Disperse Red 1 (DR 1). The first hyperpolarizability was highly related to the structure of the related carbazole-azo binary compound. Using their doped poly(methyl methacrylate) (PMMA) films, a refractive index change of these films was determined up to 0.0010 at the incident wavelength of 632.8 nm in the two-photon holography experiment. This demonstrated that these compounds exhibited a strong two-photon behavior.