Remarkable Enhancement of Second-Order Nonlinear Optical Properties of Polynorbornenes Having Pendant Chromophores. Use of Hyper-Rayleigh Scattering to Estimate the Tacticity of Rigid Rod Polymers

Second-order nonlinear optical devices can be constructed by arranging the organic chromophores as pendants into a supramolecular backbone. 1-4 Enhancement of such nonlinearity has been observed when chromophores are organized in a fixed noncentrosymmetric arrangement as side groups of helical polyisocyanide and polypeptide. 1 However, no enhancement on the first hyperpolarizabilityâ0 values was observed for chromophores incorporated into a polymer with a flexible backbone. 4 The use of more rigid polymers such as polynorbornenes (PNB) derived from the ring-opening metathesis polymerization (ROMP) of norbornene derivatives in optoelectronic applications has been briefly explored. 5-7 The versatility of this methodology was demonstrated by synthesizing liquid crystalline polymers, 5 electroluminescent polymers, 6 and multiblock copolymers bearing various aryl chromophores to study their steady-state emission. 7