ELECTROOPTIC EFFECTS IN 2 TOLANE SIDE-CHAIN NONLINEAR-OPTICAL POLYMERS - COMPARISON BETWEEN MEASURED COEFFICIENTS AND 2ND-HARMONIC GENERATION

The electro-optic coefficients for the chromophore nitroamino tolane [NAT:HOCH2CH2-N(C2H5)-phi-C=C-phi-NO2] attached to either a poly(methyl methacrylate) or an epoxy polymer have been measured by three different techniques: attenuated total reflection, ellipsometric reflection, and Mach-Zehnder interferometry. All the results for r33 and r13 were consistent and in agreement. A comparison of these experimental methods is given. The ratios between the electro-optic coefficients and the relationships between the coefficients and the second-harmonic components give additional information about these nonlinear-optical polymers. Interestingly, it was found that the observed electro-optic coefficients increased after the samples had aged a few months.