Аннотация:Abstract—Abnormal changes have been found in the viscosity of aqueous poly(vinyl alcohol) solutions with different concentrations (1–8%) exposed to UV irradiation for 0–60 min. A molecular mechanism of this phenomenon has been proposed based on the assumption of a rearrangement in the hydration shells of the functional groups of poly(vinyl alcohol) as a result of changes in the environment under the influence of UV irradiation.