A novel NLO azothiophene-based chromophore: Synthesis, characterization, thermal stability and optical nonlinearity

This letter reports a new class of nonlinear optical (NLO) chromophores, of which 2-dicyanomethylen-3-cyano-4-{2-[2-(4-( N , N -di(2-hydroxyethyl)-amino)phenylazo)-thien-5]- E -vinyl}-5,5-dimethyl-2,5-dihydrofuran ( 2a ) is the prototype with high thermal stability and large optical nonlinearity. Chromophore 2a was synthesized based on the azothiophene conjugated spacer and TCF electron-withdrawing acceptor, and characterized by IR, UV–Vis, MS and NMR spectra. A high decomposition temperature of 244 °C was determined by TGA measurement, and a first hyperpolarizability (zero-frequency hyperpolarizability, β 0 ) as large as 800 × 10 − 30 esu was estimated by HRS technology.