The Evolution of Bullet Resistant Glass

Kings, queens, presidents, dictators, criminals and religious leaders have vehicles with windows made from bulletproof glass. Actually, the term is a bit of a misnomer. A Houston glass company would be more likely to call it bullet resistant at the consumer level. Truly bulletproof glass is very thick and beyond the reach of the average person. It is also impractical for use in most Houston residential glass applications.

Bulletproof glass is made from layers of laminated glass or polycarbonate thermoplastic that can withstand the impact of small-arms fire. Its level of protection depends on the thickness and the way it prevents bullets from penetrating the window. Despite the layers, it still retains the transparency of normal automotive glass. It can even be tinted.

In the most basic type of bullet resistant glass, the outer layer of plastic slows the projectile, which then hits a layer of regular glass. The glass layer flattens the bullet and prevents it from piercing the window. Bulletproof glass is made from several layers of glass with ethylene-vinyl acetate, polyurethane or polyvinyl butyral sandwiched between the glass layers. The principle is that each subsequent layer stretches thanks to its elasticity, which slows the bullet’s momentum enough that it either ricochets off or is stopped.

Historic Uses of Bulletproof Glass

The first bulletproof glass, like most inventions, was accidental. In 1903, French chemist Edouard Benedictus dropped a flask that contained plastic cellulose nitrate, which had coated the glass with a plastic lining. To his surprise, the flask did not break. Benedictus immediately realized the implications for a shatter-resistant glass. His experiments produced a laminated safety glass that could resist a blow from a hammer. This led to the first pairs of safety glasses in 1909. He patented the product in France and the United States.

Advances in the technology resulted in the safety glass being used for the eyeholes of World War I gas masks. It was also installed in airplane windshields and used for aviator goggles. A few years later, banks began using the glass to protect their tellers. The panes of glass were outfitted with a speaker to facilitate communication between the customers and the bank workers.

In 1930, bulletproof glass was first used in cars. It was so expensive that only wealthy individuals and criminals could afford it. A much thicker version of the glass was used in World War II. It was installed in military vehicles to protect soldiers on the battlefield. Bulletproof glass was installed as a precautionary measure in the Oval Office at the White House after the Japanese bombing of Pearl Harbor.

During the mid-1950s, The Louvre art museum put the Mona Lisa behind bulletproof glass after it was attacked by rocks and acid. The glass was used when the painting was on-site or when it was on loan to other museums across the world. The glass protected Leonardo Da Vinci’s masterwork when it was again attacked in 1974 and 2009.

After John Kennedy’s assassination, President Lyndon Johnson recited his Oath of Office behind bulletproof glass. The Vatican had it installed in Pope John Paul II’s vehicle in 1981 after an attempt was made on his life.

A U.S. patent was given to bulletproof glass on March 22, 1982. This material was more robust than the shatterproof glass that Benedictus patented.

Contact Northwest Glass and Mirror at 281-463-7801 if you are interested in learning more about bulletproof and bullet resistant glass. We specialize in all types of glass applications, including Houston residential mirrors, shower enclosures, tabletops, shelving, doors and windows. Our glaziers have over 35 years of experience restoring, repairing and replacing commercial and residential glass. We can help you make important decisions that will have your home or business looking beautiful from the outside or within.