Accession Number : AD0783716

Title :   Brillouin, Rayleigh and Depolarized Rayleigh Scattering Studies of Polypropylene Glycol I.

Descriptive Note : Technical rept. no. 7, 1 Apr-7 Aug 74,


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

Report Date : 07 AUG 1974

Pagination or Media Count : 36

Abstract : A comprehensive light scattering study of an important polymer, polypropylene glycol, having an average molecular weight of about 425 (PPG 425) was carried out. From the polarized spectra, the velocity and attenuation coefficient of the longitudinal hypersound as a function of temperature were determined. Measurements of the velocity and attenuation coefficient indicate the presence of molecular relaxations between 250 to 390K. A maximum in the sound attenuation versus temperature curve was observed. The Landau-Placzek ratio over a wide range of temperature was also measured and compared with the theory of Litovitz and coworkers on the relaxing molecular liquid over a wide temperature range. Depolarized scattering studies were also carried out. The molecular reorientation time and activation energy are determined from the spectral linewidth measurement as a function of temperature. Depolarization ratios were determined. The Krishnan effect was observed at temperatures below 250K. (Modified author abstract)

Descriptors :   *Light scattering, *Rayleigh scattering, Temperature, Glycols, Polymers, Brillouin zones, Depolarization, Molecular weight, Modulus of elasticity, Polarization, Liquids, Hypersonic velocity, Acoustic waves

Subject Categories : Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE