Abstract: Glass having improved hydrolytic and chemical resistance as well as improved water repellency and mechanical characteristics is obtained by reacting the glass surface with an organoborosiloxane polymer, substituted by one or more of alkyl, aryl, alkoxy, acyl radicals, said organoborosiloxane polymer containing no free hydroxy groups in the presence of one or more organic Ti, Zr, Sn, v compounds at a temperature comprised between 200.degree. and 400.degree.C in order to obtain, through a grafting reaction, a superficial layer of modified glass.