The development of tempered glass can be traced back to the middle of 17th century, when a king named Robert had done an interesting experiment, he put a drop of molten glass in the cold water, resulting in a very hard glass. This high-strength granular glass, like water droplets, drags long, curved tails, known as "Prince Robert". But when the tail of the small grains is bent and broken, it is strange that the whole small grains suddenly collapse violently, even into fine powder. The above approach, much like metal quenching, and this is the quenching of the glass. This quenching does not make any changes to the composition of the glass, so it is called the physical quenching (physical tempered), so the tempered glass is called quenching glasses (tempered glass).
The first patent for fiberglass was obtained by the French in 1874, tempered by heating the glass to near the softening temperature and immediately putting a of the relatively low temperature into the liquid tank to increase the surface stress. This method is the early liquid tempering method. Germany's Frederick Siemens won a patent in 1875, and Geovge E. Rogens in Massachusetts, USA, applied the toughened method to glass glasses and lamp posts in 1876. In the same year, New Jersey's Hugho ' Heill won a patent.