Azo chromophore functionalized polythiophenes.: Synthesis and nonlinear optical properties

New polythiophene derivatives containing azo dye side group were prepared via copolymerization of 3-alkylthiophenes and Disperse Red I substituted thiophenes. The presence of chromophore groups in the polymers was confirmed by NMR and FTIR spectroscopies as well as by elemental analysis, The obtained soluble polymers were processed into thin films by spin coating technique and their nonlinear optical properties were studied by the optical second harmonic generation technique and by quadratic electro-optic Kerr effect. The second order nonlinear optical coefficients are: d(sp) = 6.8 pm/V and d(pp) = 28.3 pm/V at 1064 nm fundamental wavelength. The quadratic electro-optic Ken coefficient is about three times larger for the unfunctionalized polymer than for unfoncionalized.