Stability of Electric Field Induced Ordering in a UV-Curable Polymer System

The stability of the electric field induced ordering in a UV-curable polymer system is studied by probing the second harmonic generation (SHG) process. The held induced SHG intensities from the polymer film are measured as a function of the azimuthal angle for rotation at oblique incidence in various polarization geometries. The symmetry group of the polymer film under the electric field is unambiguously determined, and the effective nonlinear optical (NLO) susceptibilities are obtained from the SHG intensity profiles. The field and temperature dependence of the NLO susceptibilities are described in terms of the third-order optical nonlinearity.