Float glass is an important kind of commercial glass used in buildings and automobiles or other vehicles. It is produced in the so-called float process, in which the glass melt floats on a bath of molten tin while cooling and solidifying. The stoichiometry of the surface layer differs from that of the bulk and will sometimes change due to subsequent high-temperature process steps and attack by water or humidity. Float glass samples which had undergone a defined hydration treatment were investigated by means of NRA ( 15N technique) and RBS. We report on the observed alterations in the depth distributions of sodium and hydrogen caused by controlled temperature treatment (up to 400°C).