New side-chain polyurethanes with highly conjugated push-pull chromophores for second order NLO applications

Six new side-chain polyurethanes with large molecular hyperpolarizabilities were synthesized by reaction of ethylenic and/or azo bridged push-pull chromophoric monomers with tolylene 2,4-diisocyanate. The NLO-phores show different conjugation pathway but analogous donor/withdrawing substituents. The chemical and thermal properties of the chromophores and of the polymers were examined. Evaluation of the second order NLO properties was performed by EFISH determination of μβ on the monomers, and by SHG measurements on some amorphous thin films obtained from polymers through spin-coating technique.