New third-order nonlinear polymers functionalized with Disperse Red and Disperse Orange chromophores with increased stability

New and very stable polymers with good optical third-order nonlinearities have been prepared by condensation between a copolymer of maleic anhydride and octadecene and appropriate Disperse Red and Disperse Orange type chromophores. The nonlinear response of low concentration solutions of the polymers has been determined using a new numerical Z-scan technique. The polymers have been found highly stable, and their nonlinear response is very reproducible, both under intense illumination and upon several repeated experiments over months. Especially the polymer where the Disperse Orange 3 chromophore is incorporated in the main chain through imide linkages displays both the highest refractive nonlinearity and almost no two-photon absorption. Its surprisingly higher nonlinear response with respect to the parent Disperse Orange 3 is demonstrated and discussed.