An Attempt To Modify Nonlinear Optical Effects of Polyurethanes by Adjusting the Structure of the Chromophore Moieties at the Molecular Level Using “Click” Chemistry

Abstract

The modification of the nonlinear optical effects (NLO) properties of polyurethanes by adjusting the structure of chromophore moieties at the molecular level by introducing different size of isolation spacers, was illustrated. One of the major problems arising while optimizing organic NLO materials is to efficiently translate the large β values of the organic chromophores into high macroscopic NLO activities of polymers. The isolation parts in the chromophore moieties can weaken the strong intermolecular electrostatic interaction to enhance the resultant macroscopic NLO effect of polymers. The dynamic thermal stabilities of the NLO activities of the polymers are investigated by depoling experiments where the real time decays of their SHG signals are monitored. The results show that the NLO properties do not always increase accompanying with the entanglement of the isolation groups linked to the corresponding chromophore moieties.