Abstract <p>The authors study morphological changes in surfaces and chemical transformations caused by the thermal annealing and aging of tungsten films 0.05–0.12 μm thick, applied via chemical vapor deposition onto the surfaces of glass microspheres. It is shown that features of thermochemical processes and the change in the electrical impedance of the tungsten films during aging are caused mainly by the formation of tungstic acid hydrate and tungsten oxides, accompanied by the formation of nanorelief on the films’ surfaces. The oxidation of tungsten on a surface of sodium silicate glass begins at a temperature of 430°C and is accompanied by the formation of mainly δ-WO₃, γ-WO₃, and Na₅(W₁₄O₄₄) at a temperature of 530°C. Local zones of refractory sodium tungstate and ditungstate form on the surface of the glass spheres at a temperature of 920°C.</p>