polymers are disclosed alkali metal carboxylic acid catalyst is also disclosed as well as the incorporation of cerium oxide for attenuation of ultraviolet radiation application_number US 77186001 A description commercial abrasion resistant coatings for stretched acrylic either contain colloidal silica and exhibit poor resistance to corrosion by solvents such as acetone and sulfuric acid or are based on relatively soft organic polymer systems such as urethanes or melamines the hydrolysis of silanes of the general formula r x si or u2032 4 x wherein r is an organic radical r u2032 is a hydrolyzable low molecular weight alkyl group and x is at least one and less than 4 such as methyltrimethoxysilane dimethyldiethoxysilane and u03b1 methacryloxypropyltri ethoxysilane can be carried out under controlled conditions in the presence of appropriate additives and produces stable clear solutions that exhibit excellent adhesion to unprimed stretched or cast acrylic cured coatings preferably about four microns thick typically exhibit bayer abrasion results i e percent haze after 300 cycles of one kilogram load of 5 10 percent have a stress crazing time of 17 minutes upon exposure to acetone and 30 minutes upon exposure to 75 sulfuric acid under 3000 pounds per square inch pressure and remain crack free for up to 1900 hours of ultraviolet radiation exposure preferably the silane hydrolytic polycondensation is catalyzed by an appropriate acid which is volatile and which does not lower the ph of the solution excessively preferred catalysts include acetic acid and trifluoroacetic acid and sodium acetate a preferred ph is about 5 the temperature of the hydrolytic polycondensation reaction must be controlled either by external cooling or by adjusting the solvent and acid composition to control the reaction rate preferably not to exceed 45 u00b0 c a catalyst preferably sodium acetate is added to.