DETERMINATION OF THE OPTICAL ANISOTROPY OF ATACTIC POLYSTYRENE USING A GRATING MONOCHROMATOR

To extract the intrinsic molecular scattering from unwanted collision- induced contributions as much as possible we propose a simple useful m ethod recording the depolarized Rayleigh spectra using a double gratin g monochromator and correcting the spectra for the high-frequency wing s. For this purpose we tested the system polystyrene/CCl4 for which an asymptotic value of the optical anisotropy (gamma(2))/x congruent to 30 Angstrom(6) with degree of poly merization x > 20 was found. The de polarized Rayleigh intensity of 2,4-diphenylpentane and anionically po lymerized atactic polystyrene standards was also measured in dilute so lutions in the B-solvent bicyclohexyl (theta = 61 degrees C). From the absolute depolarized Rayleigh ratio we obtained the configurational a verage optical anisotropy per number of monomer units, (gamma(2))/x. W e have chosen cumene as a model compound estimating that its optical a nisotropy is similar to that of a quasi monomer unit. No significant t emperature dependence of (gamma(2))/x and of the static internal pair correlation in the temperature range from 25 degrees C up to 80 degree s C was found.