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The phase behavior of a model polymer solution, polystyrene in methyl aceate, has been investigated by means of static light scattering. Rayleigh ratios and correlation lengths have been measured over a broad range of temperatures (300-400 K) and concentrations (0.5-10.3 wt %). A novel procedure to correct the measured forward scattered intensity for turbidity has been applied. Rayleigh ratios have been used to determine values of the free energy curvature (d2AG/dc2) in the homogeneous one-phase region of this system, i.e., between the upper and lower critical phase boundaries. The complete data set forms a unique basis which can be used to test thermodynamic model predictions.

Depolarized light scattering spectra of normal and supercooled water have been measured between 298 and 246 K. The depolarization ratio Zvv(w)/ZvH(w) is 4/3, independent of frequency and temperature. By application of the second-order, dipole-induced-dipole mechanism and by use of neutron and X-ray scattering data, it is argued that the low-frequency part of the spectra is dominated by single-particle, diffusive motion. The high-frequency part of the spectra reflects the relaxation of the center of mass velocity. This motion becomes more pronounced when supercooling proceeds.Depolarized Light Scattering from Supercooled Water

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