Chemical properties, roughness and composition of glass surface formed on water vapour at high temperature (over 1000 deg C) was investigated. Atomic force microscopic (AFM) measurement showed that the treated surface is as smooth as the surface of a typical float glass. The treated surface has higher chemical resistance than the non-treated surface, because sodium and calcium were extracted near the surface. From the experiment with the use of isotope labelled waters, D20 and H218O, instead of H2O, it was found that the depth of the reacted layer with the water vapour was estimated about 30um, and that oxygen atoms of the water vapour replaced those of the original glass. The mechanism of the alkali ion extraction from the surface was also discussed.
