Linear Electro-Optic measurements of Dye-Doped Polymers

Abstract

The basic Mach-Zehnder interferometer was modified for use in in-situ temperature dependent linear electro-optic (LEO) measurements of thin films of 4-dimethylamino-4'-nitrostilbene (DANS) doped into poly(methyl methacrylate) (PMMA). Optimum interferometer phase stability was possible because of an incorporated electronic feedback system. Film thickness variation was compensated for in order to obtain more accurate LEO coefficient measurements and thus the second order susceptibility. Moreover, both the α-relaxation associated with the glass transition, Tg, and β-relaxation associated with the secondary transition occurring below Tg of PMMA + 2%wt.DANS were obtained.