Process for coating a synthetic polymer sheet material with a durable abrasion-resistant vitreous composition

The method of coating a sheet of material of diallyl glycol carbonate polymer comprising the steps of:

• 1. first step -- hydroxylating the sheet surface to be coated;
• 2. second step -- applying to the hydroxylated surface of the sheet by vacuum deposition a base coating of a material selected from the group consisting of silicon monoxide and a mixture of silicon dioxide and silicon monoxide, by evaporation of silicon monoxide in an oxygen atmosphere under a vacuum lower than 1 .times. 10.sup.-4 torr, said base coating being at least one molecule in thickness;
• and
• 3. third step -- applying to the coated surface of the sheet of the second step by vacuum deposition an outer coating of evaporable glass, said evaporable glass being in a thickness of about one micrometer or higher, said glass coating being applied at a pressure lower than 5 .times. 10.sup.-4 torr.