[en] Electrochromic effects of WO/sub 3/ films have been extensively studied. In these electrochromic films, the injection of both I-group ions and electrons form a tungsten bronze (color center) structure (M/sub x/WO/sub 3/, x=0-1, M is H, Li, or Na). It is known that an intervalence electron transfer between W/sup +6/ and W/sup +5/ causes blue coloration in these films. Previously, the authors reported a new fabrication method and the properties of double-layered Li-W-O films. The WO/sub 3/ films exhibit photochromic effects as well as electrochromic effects. In this paper they describe the electrochromic effects of the double-layered Li-W-O films under UV light