Strictly, Bulletproof glass would be glass that is capable of stopping all manner of bullets fired at it. Such glass cannot currently be made in any usable thickness (if at all), so what is loosely called Bulletproof Glass is, within the industry, referred to as Bullet resistant glass. Glass can be made transparent and flat, or into other shapes and colors as shown in this sphere from the Verrerie of Brehat in Brittany. ...

Bulletproof Glass is usually constructed using a strong but transparent material such as polycarbonate thermoplastic or by using layers of laminated glass. The desired result is a material with an appearance and light-transmitting behaviour of standard glass but offers varying degrees of protection from small arms fire. Transparent glass ball In optics, transparency is the property of allowing light to pass. ... Polycarbonates are a particular group of thermoplastic polyesters. ... A thermoplastic is a material that is plastic or deformable, melts to a liquid when heated and freezes to a brittle, glassy state when cooled sufficiently. ... A laminate is a material constructed by uniting two or more layers of material together. ... Small arms captured in Fallujah, Iraq by the US Marine Corps in 2004 The term small arms generally describes any number of smaller infantry weapons, such as firearms that an individual soldier can carry. ...

The polycarbonate layer, usually consisting of products such as Cyrolon, Lexan and Tuffak, is often sandwiched between layers of regular glass. The use of plastic in the laminate provides impact-resistance, such as physical assault with a hammer, an axe, etc. The plastic provides little in the way of bullet-resistance. The glass, which is much harder than plastic, flattens the bullet and thereby prevents penetration. This type of bullet resistant glass is usually 70-75 mm thick. Bottles made of Lexan LEXAN® is a registered trademark for General Electric Companys brand of highly-durable polycarbonate resin thermoplastic intended to replace glass where strength justifies its cost. ...

Bullet resistant glass constructed of laminated glass layers is built from glass sheets bonded together with polyvinyl butyral or polyurethane. This type of bullet resistant glass has been in regular use on combat vehicles since World War II; it is typically about 100-120 mm thick and is usually extremely heavy. Polyvinyl butyral (or PVB) is a resin usually used for applications that require strong binding, optical clarity, adhesion to many surfaces, toughness and flexibility. ... A polyurethane is any polymer consisting of a chain of organic units joined by urethane links. ... Combatants Major Allied powers: United Kingdom Soviet Union United States Republic of China and others Major Axis powers: Nazi Germany Italy Japan and others Commanders Winston Churchill Joseph Stalin Franklin Roosevelt Harry Truman Chiang Kai-Shek Adolf Hitler Benito Mussolini Hideki Tojo Casualties Military dead: 17,000,000 Civilian dead...

One-way bullet resistant glass

Advances in bullet resistant glass have led to the invention of one-way bulletproof glass, such as used in some bank armored cars. This glass will resist incoming small arms fire striking the outside of the glass, but will allow those on the other side of the glass, such as guards firing from inside the armored car, to fire through the glass at the exterior threat. An armored car ( or armoured car in British English) is one of several types of wheeled armored vehicles: a civilian bullet-proof passenger car, a military wheeled armored vehicle, or a special-purpose armored cargo vehicle for transporting valuables. ...

One-way bulletproof glass is usually made up of two layers, a brittle layer on the outside and a flexible one on the inside. When a bullet is fired from the outside it hits the brittle layer first, shattering an area of it. This shattering absorbs some of the bullet's kinetic energy, and spreads it on a larger area. When the slowed bullet hits the flexible layer, it is stopped. However, when a bullet is fired from the inside, it hits the flexible layer first. The bullet penetrates the flexible layer because its energy is focused on a smaller area, the brittle layer then shatters outward due to the flexing of the inner layer and does not hinder the bullet's progress. Kinetic energy is the energy that a body possesses as a result of its motion. ...

A glass's ability to withstand shock is also helped by the annealing process of tempering. When treated at the right temperature, the glass remains harder, which means it takes more force to shatter the surface. The word anneal has several meanings: In metallurgy and materials science annealing is a heat treatment wherein the microstructure of a material is altered, causing changes in its properties such as strength and hardness. ... Tempering is a heat treatment technique for metals and alloys, most often the toughening of martensitic steel. ...

Recent advances in bullet resistant glass composition

U.S. military researchers are moving quickly to develop a new class of transparent armour incorporating aluminium oxynitride (Trade name: AlON) as the outside "strike plate" layer.^[1] It is much lighter and performs much better than traditional glass/polymer laminates. This allows aluminium oxynitride "glass" to defeat threats surpassing .50 caliber armor piercing rounds using material that is not prohibitively heavy. Aluminium oxynitride (AlON) is a transparent ceramic composed of aluminium, oxygen and nitrogen. ... An M2 machine gun surrounded by spent shell casings The M2 . ... An Armour piercing shell is a type of ammunition designed to penetrate armour. ...

See also

• Prince Rupert's Drops

Prince Ruperts Drops (or Ruperts Balls) are a glass curiosity created by dripping hot molten glass into cold water. ...

References

External links

• Bullet Proof Glass Manufacturer & Fabrication