Preparation and characterization of thiophene copolymers with second order non-linear optical properties

Abstract Azobenzene-substituted polythiophenes were prepared by copolymerization of 3-alkylthiophenes functionalized with an azo-chromophore and 3-alkylthiophenes as plastifying comonomers to improve solubility. Monomers with different oligomethylenic spacer and alkylic chain lengths were synthesized and copolymerized via FeCl 3 oxidative polymerization. Polymer soluble fractions were characterized by 1 H and 13 C NMR, FTIR, UV–Vis spectroscopy, and GPC, DSC and TGA. Second-order non-linear optical properties were measured by the second harmonic generation technique.