TRANSIENT INHOMOGENEITIES IN POLYMERIC LIQUIDS AND SOLUTIONS - CHARACTERIZATION BY STATIC AND DYNAMIC LIGHT-SCATTERING

Low molecular weight liquid polyisoprenes and concentrated solutions o f polystyrene in toluene were studied by static and dynamic light scat tering. Besides the well known density and concentration fluctuations, both systems show an additional slow relaxation mode which is accompa nied by a strong scattering at small angles. The relaxation rate of th e process is proportional to the square of the scattering vector q. Th e process seems to be due to the motion of clusters inside the sample. Small angle light scattering experiments indicate a cluster size of t he order of 10(-7) m. After several months the clusters disappeared. F or the samples under study, cluster formation therefore constituted a non-equilibrium phenomenon.