New azobenzene-containing polyurethanes: Post-functional strategy and second-order nonlinear optical properties

A new series of azobenzene-containing polyurethanes were prepared and post-azo coupling reactions were successfully used to modify the subtle structure of the azobenzene chromophore moieties. The polymers were characterized and their nonlinear optical properties were investigated by means of second harmonic generation processes. One of the polymers exhibited highest nonlinear optical effects (d33 = 58.2 pm/V), in which carbazolyl moieties were introduced to the chromophore groups as the isolation moieties. The results demonstrate the possibility of controlling the properties of polymers after the polymerization process.