Abstract

We present a generalized model for the electro-optic response of chromophores in a viscoelastic polymer matrix to a combined dc and ac applied poling field. The model includes a local molecular field of random orientation at each chromophore site to take into account the influence of the polymer matrix on the chromophore reorientation. Hence the model relies on a physically intuitive picture of chromophore dynamics in a viscoelastic polymer matrix. The dynamics is described by the rotational diffusion equation, where the local molecular field is inferred and a solution is presented with a variational approach. We obtain an analytical expression for the electro-optic response both at the modulating frequency and at two times the modulating frequency, having explicit frequency and molecular-field dependence. The model is successfully compared with frequency-resolved ellipsometric measurements in an azo-dye containing polymer guest–host system that is poled in a combined dc and ac electric field. The experimental setup is a modified Teng–Man ellipsometer in a balanced detection scheme, and, as a model system for investigating the electro-optic response, we use the chromophore Disperse Red 1 in a polymer matrix of poly(methyl methacrylate). Finally, the model is compared with independent experiments on a 2,5-dimethyl-4-(p-nitrophenylazo)-anisole containing photorefractive polymer composite, and good qualitative agreement is found.

© 2003 Optical Society of America

dc and ac Electro-optic response of chromophores in a viscoelastic polymer matrix: analytical model

Thomas G. Pedersen, Kim Jespersen, Per M. Johansen, and John Wyller
J. Opt. Soc. Am. B 19(11) 2622-2631 (2002)

Chielectric relaxation: chromophore dynamics in an azo-dye-doped polymer

W. N. Herman and J. A. Cline
J. Opt. Soc. Am. B 15(1) 351-358 (1998)

Modeling relaxation processes in poled electro-optic polymer films

R. D. Dureiko, D. E. Schuele, and K. D. Singer
J. Opt. Soc. Am. B 15(1) 338-350 (1998)

Birefringent and electro-optic effects in poled polymer films: steady-state and transient properties

J. W. Wu
J. Opt. Soc. Am. B 8(1) 142-152 (1991)

Ellipsometric measurements of poling birefringence, the Pockels effect, and the Kerr effect in high-performance photorefractive polymer composites

Sandalphon, B. Kippelen, K. Meerholz, and N. Peyghambarian
Appl. Opt. 35(14) 2346-2354 (1996)