[en] The process of tungsten trioxide amorphous film hydration under effect of aqueous electrolyte is investigated by infrared spectroscopy and optical measurement methods. It is shown that quantity of water molecules introduced to WO₃ film under hydration and the type of hydrogen bonds produced by these molecules with tungsten-oxygen octahedrons determine the structure of crystallohydrates of hydrated produced. Electrochromium properties of hydrated films are investigated. Dependence between the crystallohydrate structure and the magnitude of electrochemic absorption band maximum shift to the infrared spectrum region is detected