Accession Number : AD0776665

Title :   Brillouin and Rayleigh Scattering in Polybutadiene.

Descriptive Note : Technical rept. no. 5, 1 Apr 73-31 Mar 74,


Personal Author(s) : Huang,Y. Y. ; Wang,C. H.

Report Date : 22 MAR 1974

Pagination or Media Count : 27

Abstract : The molecular light scattering of polybutadiene from 110 to 350K was carried out. The study includes the measurements of Brillouin shift, Brillouin linewidth and Rayleigh depolarization ratios as a function of temperature. It has been found that the hypersonic frequency displays a discontinuity at the glass temperature Tg. The hypersonic attentuation coefficient over one wavelength has also been determined as a function of temperature. No quantitative theory has been found to be able to describe the sound attenuation above Tg. The Krishnan effect was also observed below 250K. This is the first experiment which observes the evolution of the Krishnan effect. It has been pointed out that the frozen-in density fluctuation mechanism fails to explain the effect. The frozen-in fluctuations of the dielectric anisotropy is suggested to be a possible mechanism for the Krishnan effect. (Modified author abstract)

Descriptors :   *Polybutadiene, *Rayleigh scattering, Phonons, Hypersonic characteristics, Glass, Phase studies, Spectral lines, Depolarization, Brillouin zones, Variations, Density

Subject Categories : Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE