Final answer:
Bullet-resisting glass consists of layers of durable glass, such as aluminosilicate, combined with interlayers that absorb and disperse impact energy, making it resistant to bullets. Aluminosilicate glass is chosen for its superior durability and thermal resistance, despite being more challenging to work with compared to more common soda-lime-silica glass, which is less suited for security applications.
Step-by-step explanation:
Bullet-Resisting Glass Composition
Bullet-resisting (BR) glass is a specialized type of safety glazing material designed to resist the force of bullets. This type of security glass is typically laminated, consisting of multiple layers of glass and interlayer materials that together create a strong, resistant barrier. While there are various compositions of BR glass, common features include layers of aluminosilicate or other types of glass that offer enhanced durability and thermal resistance, although they are more challenging to shape due to their high melting points. These are combined with interlayers made from materials such as polycarbonate or acrylic to absorb and disperse the energy of a bullet upon impact, aiding in the glass's bullet-resistant properties.
Ordinary soda-lime-silica glass, another common type of glass, is distinct from aluminosilicate compositions in its ease of formation and suitability for everyday products like window panes and tableware. However, this type of glass exhibits higher thermal expansion and lower heat resistance compared to aluminosilicate glass, making it unsuitable for bullet-resistant applications. Instead, the more durable silicate glasses are preferred for such safety-critical applications.