Friday 1st January 1937
Safety glass in windshields became mandatory in Great Britain. Unlike ordinary glass, safety glass shatters into thousands of tiny pieces when it breaks, instead of large jagged sheets. In early automobile accidents, ordinary glass windows often turned into large, deadly blades. Broken safety glass is relatively harmless. The most common type of safety glass is a sandwich in which a layer of clear, flexible plastic is bonded between two layers of glass. It was first produced in 1909 by French chemist Edouard Benedictus, who used a sheet of clear celluloid between glass layers. Various plastics were tried over the years. In 1936, a plastic called polyvinyl butyral (PVB) was introduced. It was so safe and effective that it soon became the only plastic used in safety windows. The British government was so impressed by the safety record of PVB windows that it required their use by law.