Chi-electric Relaxation: Frequency Domain Chromophore Dynamics in Nonlinear Optical Polymers

Abstract

The orientational stability of nonlinear optical chromophores in polymer systems has been the subject of extensive research.1-8 A new experimental method of observing chromophore dynamics has been developed. The method is similar to dielectric relaxation measurements where the linear polarization of the material is induced by a sinusoidal electric field. However, this new method probes the orientation of just the chromophores through second harmonic generation (SHG). This method is unique because it yields information about chromophore dynamics in the frequency domain, whereas the bulk of the work is done in the time domain. The method is dynamic and the chromophores are in steady-state motion in response to a time varying electric field, as opposed to studies such as Boyd et al.4 where measurements are made with a static electric field. A description of the experimental method and a discussion of the results follows.