Laminated glass was invented in 1903 by the French chemist Edouard Benedictus, inspired by a laboratory accident. A glass flask had become coated with the plastic cellulose nitrate and when dropped shattered but did not break into pieces. Benedictus fabricated a glass-plastic composite to reduce injuries in car accidents.[citation needed] It was not immediately adopted by automobile manufacturers, but laminated glass was widely used in the eyepieces of gas masks during World War I.
By 1939 some 600,000 square feet (56,000 m2) of "Indestructo" safety glass was being used every year in vehicles produced at the Ford Motor Company works in Dagenham, England.[1] "Indestructo" safety glass was manufactured by British Indestructo Glass Ltd of London.[1] This was the laminated glass used by the Ford Motor Company in 1939, chosen because "it gives the most complete protection. In addition to being splinterproof it is crystal clear and permanently non-discolourable.".[1] This quote hints at some of the technical issues, problems and concerns that stopped laminated glass from being widely used in automobiles immediately after it was invented.
Modern laminated glass is produced by bonding two or more layers of ordinary annealed glass together with a plastic interlayer, usually polyvinyl butyral (PVB). The PVB is sandwiched by the glass which is either passed through a series of rollers and ovens to expel any air pockets and form the initial bond or placed under vacuum to remove bubbles then heated to form the initial bond. These constructions are then heated under pressure in an autoclave to achieve the final product. The tint at the top of some car windshields is in the PVB.