HIGHLY POLAR CHROMOPHORES IN POLED POLYMER-FILMS CHARACTERIZED BY 2ND-HARMONIC GENERATION

Evidence for exceptionally high dipole moments in a series of nonlinea r optical chromophores doped into poly(methyl methacrylate) films has been found. The strength of the poling field/dipole interaction is mea sured directly from incidence angle dependence of the second harmonic (SH) intensity generated from corona poled films. Values of the dipola r orientation parameter, [cos theta], greater than 0.5 can be achieved for externally applied fields of only 50 MV m(-1). Quantum chemical c alculations of the evolution of the dipole moments of the compounds ve rsus local reaction field support the conclusion that extremely high d ipole moments characterise these molecules.