Article contents
Relaxation Phenomena in Poled Electro-Optic Polymers
Published online by Cambridge University Press: 16 February 2011
Abstract
The relaxation of the nonlinear optical coefficient of poled electro-optic polymers remains an important issue in the potential application of these Materials. This relaxation is due to the homogenization of the orientational distribution function of nonlinear chromophores in the polymer glass over time. We have measured the relaxation using optical second harmonic generation as a function of temperature for doped polymer materials over a range of temperatures deep in the glassy state. We relate the data to widely used physical models of the glassy state which indicate that the relaxation process occurs over a considerable range of time scales. It has been found that the decay of the nonlinear polarization exhibits two mechanisms depending on the time and temperature scales over which measurements are performed. We have carried out measurements over a range of times and show that a broad distribution of relaxation times characterizes the data. This broad distribution is an appealing model in that it not only fits the data well, but is well connected to accepted physical models of the relaxation behavior of glasses. The characteristic energy of the relaxation can be estimated from the temperature dependence and is found to be equal to or less than the energy characterizing the polymer Motion, and agrees with dielectric studies. This indicates that the chromophores are more or less coupled to the dynamics of the polymer chain. A figure of merit for the coupling of the chromophore to the polymer chain is proposed.
- Type
- Research Article
- Information
- Copyright
- Copyright © Materials Research Society 1994
References
REFERENCES
- 2
- Cited by