Back to all articles

The History of Tempered Glass

While attempts to create tempered, or strengthened, glass have occurred throughout history, it was Harold McMaster who invented the first modern tempered glass. After studying at Defiance College and Ohio State University, he was hired as the Libby-Owens-Ford Glass Company's first research physicist. In 1948, he founded Permaglass, Inc. where he commercialized glass tempering technology. His process for tempering glass involved heating the glass, then rapidly cooling it, leaving it stronger and more malleable at the same time. His tempered glass also had positive safety implications (tempered glass breaks into small chunks with edges that are far less sharp than non-tempered glass). Tempered glass is now used in skyscrapers and countless other applications where glass strength and safety are critical.

Share this article

card showing the history of rocking chairs

Your go-to guide for weird history facts

Subscribe to the FREE daily email that makes learning about history fun.