NEW POLYMERS WITH LARGE AND STABLE 2ND-ORDER NONLINEAR OPTICAL EFFECTS

New polymers containing disperse red dye as a nonlinear optically active chromophore in conjunction with photo-cross-linkable groups have been synthesized. These polymers are soluble in many organic solvents and can be processed into thin films by spin-coating. Second harmonic generation measurements revealed large and stable second-order nonlinear optical effects for these polymers. With the corona poling method, large resonance-enhanced second-order nonlinear optical coefficients were observed at 532 nm. It was found that introduction of flexible chain into the polymer backbone causes a decrease in the T(g) value and hence a decrease in the stability of the second-order NLO effects. It was demonstrated that for polymers 2-4, chi (2) values are stable at ca. 80-90% of their maximum values for 1000 h after electrical poling. These polymers showed large refractive index changes caused by cis-trans isomerization of azo groups when they are exposed to the UV light. The large refractive index change of these polymers has been utilized in the fabrication of channelized wave-guide structures.