Pyrex^® is a brand of borosilicate glass developed by Corning Inc. Other brand names for borosilicate glass include SIMAX and Kimax^®. Borosilicate glass is known for its ability to resist thermal shock. Borosilicate glass is composed primarily of common silicon dioxide (SiO₂) with the addition of boron trioxide (B₂O₃), sodium oxide (Na₂O), and aluminum oxide (Al₂O₃). It is the addition of boron trioxide that is responsible for its higher melting point and its low thermal expansion coefficient. Laser marking Pyrex^® is done using a 10.6 micron CO₂ laser. The laser interacts with the surface of the Pyrex^® by causing localized heat stress. With sufficient laser power, microscopic pieces of glass can be fractured and ejected from the surface creating an frosted mark without significant material removal.