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Processes that generate decay of polarization in a cross-linked, nonlinear optical polymer have been studied, and their relationship to a corresponding change in second-order nonlinearity ( ®) has been determined. Measurements of second-harmonic generation, thermally stimulated discharge current, and UV-visible absorbance have been employed to identify polarization decay resulting from relaxation of oriented molecular dipoles, migration of space charge, and chemical degradation of chromophores. The effect of process parameters on ® stability in these materials is observed and explained.

An experimental technique for calibrating the photobleaching process in a nonlinear optical material is presented. The technique depends on the existence of a sharp interface between the bleached and unbleached layers of the material which travels across the film but otherwise has a constant shape. The sharp interface of constant shape is a feature of a general model and is consistent with our experimental results. By determining the dependence of the velocity on the bleaching intensity, the order of the photobleaching kinetics is determined.

Novel difunctional nonlinear optical (NLO) azo compounds with exceptional thermal stability have been synthesized and incorporated into side-chain and cross-linked polymers. The nonlinear optical response of these polymers has been studied with second-harmonic generation and electrooptic measurements. Channel waveguide intensity modulators displayed an electrooptic coefficient of 13.1 pm/V.

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