Pyrex

Pyrex is a brand of glassware marketed for culinary and laboratory use, manufactured by Corning Incorporated. The name Pyrex originates from the glass's resistance to thermal shock, a property that allowed rapid temperature changes without cracking.

In 1915, Corning Glass Works (the predecessor of Corning Incorporated) introduced Pyrex as borosilicate glass designed for laboratory glassware. Its heat resistance, chemical durability, and clarity made it popular for flasks, beakers, and other lab equipment.

During the mid-20th century, the Pyrex brand was extended to kitchenware. In many regions, Pyrex bakeware and cookware were produced using tempered soda-lime glass instead of borosilicate, a cheaper material with different thermal performance. This created regional variations in the composition and performance of Pyrex products.

Corning continues to produce Pyrex-branded glassware, including baking dishes, mixing bowls, measuring cups, and storage containers. Some lines are explicitly borosilicate glass, while others use tempered soda-lime glass; product specifications vary by market and era.

Pyrex products are designed for oven use and, where indicated, microwave use. They are typically able to withstand heat and chemical exposure, but users should avoid sudden temperature changes, direct flame contact, or dropping the glass, which can cause breakage. In some regions, Pyrex branding has been licensed to other manufacturers, leading to regional differences in material and performance.