Corning was working to make glass stronger decades before Corning® Gorilla® Glass came along.
One of the most common misconceptions about glass is that it breaks because it’s inherently weak. While glasses that we encounter on a daily basis generally can break with relative ease, the reasons glass breaks aren’t as simple as one might think. Glass generally breaks when flaws are present or introduced and enough tensile stress, or force, is applied to those flaws. These flaws could be anything from a microscopic imperfection caused during daily use to a severe interaction with a rough surface. In the absence of flaws, glass has demonstrated strengths greater than steel, nearly approaching its theoretical strength of over 2 million pounds of force per square inch!
For experts working on Gorilla Glass, the goal has been to create a cover glass for mobile consumer electronics devices that both reduces the likelihood that flaws are generated and the effect of such flaws on glass strength and breakage. They do this by working to strengthen the glass. While Gorilla Glass may be the latest of Corning’s efforts to make glass more resistant to the wear, tear and stresses of everyday life, it’s far from the first.
More than 100 years ago, Corning’s borosilicate glass was the basis for its PYREX® product lines. Because of the glass’s composition, it was not only highly chemically-durable but also capable of withstanding an incredibly wide range of temperatures without succumbing to thermal shock, which made it ideal for cookware and labware applications. Decades later, CorningWare® was developed, furthering the ability of Corning’s cookware to withstand rapid changes in temperature. But, it’s important to note that CorningWare® wasn’t glass, exactly. Instead, it was a glass-ceramic, which means it was melted and formed as a glass, and then thermally treated so that it partially crystallized, creating durable, thermally-stable cookware. Although Corning no longer sells cookware, these innovations laid the foundation for later work by the company to find ways to make glass even more durable.
In the 1960’s, Corning developed Chemcor® glass, a chemically strengthened glass that was intended to be used in phone booths, prison windows, eyeglasses and automobile windshields. Chemcor was strengthened chemically through a process called ion exchange, which allows smaller ions from the glass to be replaced with larger ions from a chemical bath. As a result, the surface of the glass became highly compressed, and therefore less prone to the introduction of damage and the application of stresses that could lead to breakage.