AbstractLight scattering as a function of scattering angle, concentration, and temperature reveals that polyoxyethylene (POE) forms large aggregates in benzene and chloroform, while in methanol and dioxane almost complete molecular dispersion occurs. Although the solutions containing large aggregates contain a distribution of molecular weights, the angular envelopes ofc/R(θ) versus sin2θ/2 exhibit pronounced upward curvature, indicating that the aggregates are dense structures such as spheres or highly branched coils. In methanol, the angular envelopes exhibit moderate downward curvature, reflecting the essentially molecularly dispersed character of the solution and the breadth of the molecular weight distribution. In filtered solutions of dioxane, a tendency exists for minima to occur in the angular envelopes; this can be rationalized in terms of the anisotropy of the scattering. The polarized components of the scattered intensityVV, HV, VH, andHHwere studied in the scattering plane. For the large aggregatesHVis angular dependent, while in methanol and dioxaneHVis independent of angle. Heating or cooling a POE solution in benzene followed by a study of the angular envelope, shows that the aggregates are stable. Hydrodynamic measurements fail to detect the existence of the aggregates. Taking all the data into consideration, the large aggregates appear to be compact, extensively branched, anisotropic, and stabl