1 December 1991 Dielectric relaxation studies of χ2 dye containing polystyrene films
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Abstract
The dielectric relaxation characteristics of narrow molecular weight distribution polystyrene (PS) films containing the second order nonlinear optical dyes, 4-[N,N- dimethylamino]-4'-nitrostilbene (DANS) and 4-[N-ethyl, N- hydroxyethylamino]-4'-nitroazobenzene (DR1), at a level of 0.19 mole percent, are reported using time domain dielectric spectrometry. Measurements ranging from 10-4 to 10+4 Hz have allowed us to closely examine sub-Tg dipolar losses that are associated with the dye. It is seen that the frequency range over which dye relaxations occur are similar to those characteristic of the sub-Tg (beta) transition of polystyrene though with grossly different dispersion amplitudes. The dye relaxation time activation energies are 131 kJ/mol and 79 kJ/mol for DANS and DR1 respectively. The dye relaxation amplitudes do not follow predicted T-1 behavior. Extremely broad dispersion curves imply a broad distribution of relaxation times. With physical aging, little change in (beta) amplitude is seen though a narrowing of the relaxation time distribution function seems to occur. Our results indicate that in a poling experiment with near ambient temperature aging, sub-Tg (beta) losses will account for losing 17 - 20% dye orientation within a matter of seconds after field removal. Relaxations occurring over longer times arise from a combination of (alpha) and (beta) losses.
© (1991) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Michael A. Schen, Michael A. Schen, Fred Mopsik, Fred Mopsik, } "Dielectric relaxation studies of χ2 dye containing polystyrene films", Proc. SPIE 1560, Nonlinear Optical Properties of Organic Materials IV, (1 December 1991); doi: 10.1117/12.50745; https://doi.org/10.1117/12.50745
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