Second-order nonlinear optical properties and polar order relaxation dynamics in a cyano-chromophore grafted polyurethane polymer

The all-optical recording of a microscopic second-order nonlinear susceptibility in a new azo dye pendant polyurethane polymer is investigated. An experimental configuration which permits self-phase matched was used. The peak value of the phase-matched light-induced second order nonlinear optical susceptibility χ(2) measured at 1.06 μm reaches 62 pm/V at room temperature, which corresponds to a molecular orientation ratio of 30%. Temporal stability of the induced polar order measured by second harmonic generation revealed a reduced decay rate of the χ(2) value in comparison to Disperse Red 1 pendant poly(methyl methacrylate).