Abstract: Photoannealing is a technological method that allows replacing the finishing high-temperature treatment of sol‒gel metal oxide films with a combination of soft heating and UV irradiation. It has been established that an increase in temperature during heat treatment of a sol deposited onto a substrate leads to the conversion of zinc acetate into layered basic zinc acetate, which is transformed into hydroxide Zn(OH)2 and then into amorphous oxide ZnO. It has been shown that, upon heating to 130°C, parallel UV irradiation of films promotes the direct transition of layered basic zinc acetate into oxide due to the effective removal of hydroxyl and acetate groups. When the temperature is increased to 140°C, UV irradiation of the films becomes inexpedient, since both photoannealing and heat treatment lead to identical properties of the investigated materials.