Synthesis and optical properties of a carbazole-containing novel oligomer

We report on the synthesis and optical properties of a novel oligomer (oligo(2-{2-but-1-enyl-6-[2-(9-decyl-6-formyl-9H-carbazol-3-yl)-vinyl]-pyran-4-ylidene}-malononitrile)) (Olg(Cz–Pyr–CN)) with an average degree of polymerization three. The molecule was designed to have push–pull structure and was synthesized by Knovenagel condensation reaction. The resulting Olg(Cz–Pyr–CN) was characterized by means of 1H NMR spectroscopy and IR spectroscopy. The initial decomposition temperature (Tid) of Olg(Cz–Pyr–CN) appeared at 372 °C. The alignment order parameter of the poled Olg(Cz–Pyr–CN) film was 0.31. The electro-optic (EO) coefficients (r33) and their NLO properties were evaluated by simple reflection and the Maker fringe method. The EO coefficients of Olg(Cz–Pyr–CN) was found to be 28.7 pm/V at 632.8 nm.