NEW NLO POLYMERS FOR 2ND-HARMONIC AND 3RD-HARMONIC GENERATIONS

Poly(L-glutamate)s (PLG) having NLO active chromophore in side chains were synthesized by an ester exchange reaction of methyl ester of PLG with 4-(3-hydroxypropoxy)-4'-nitrostilbene or other alcohols containin g the nitrostilbene moiety, and the NLO properties of these polymers w ere investigated in terms of second harmonic generation (SHG). These p olymers exhibited rather stable poled structures after electric poling , possibly owing to the helical structures of PLG. Aromatic polymers s uch as poly(p-phenylene) are thermally stable with high glass transiti on temperatures. Poly(p-phenylene) derivatives having various donor or acceptor groups were used to measure NLO properties in terms of SHG a nd third harmonic generations (THG). They showed high SH coefficients with less relaxation behaviors of the poled structures.