Abstract: The present invention is relative to a heat-curable coating composition forming transparent tintable abrasion-resistant coatings, said compositions comprising, in an aqueous or hydro-organic solvent: (A) a hydrolysate of an epoxy-functional silane compound containing at least two alkoxy groups, (B) colloidal silica having an average particle diameter of 1 to 100 ?m, (C) an aluminium chelate compound of formula Al(O—C1-4 alkyl)nY3-n wherein n is 0, 1 or 2 and Y is a ligand selected from the group consisting of M-C(?O)—CH2—C(?O)-M and M-C(?O)—CH2—C(?O)O-M, wheren each M is independently a C1-4 alkyl group, and (D) a hydrolysate of a silylated poly(tetrahydrofurane) of formula (Ia) or (Ib) said heat-curable composition not containing any multifunctional cross-linking agents selected from the group consisting of multifunctional carboxylic acids and multifunctional anhydrides.