Bread was advertised as rising better, and pie crusts as crisping on both bottom and top. Its transparency allowed the cook to assess doneness without uncovering. Littleton had observed, that it heated evenly, actually absorbing and conducting heat rather than reflecting it as metal utensils might. While Pyrex was not the first high heat compatible glass of its kind, it certainly became the most successful in terms of both the scientific ware and kitchenware produced from it.ДЄs kitchenware, and as bakeware in particular, Pyrex was marketed as being most versatile. Corning was able to survive the poor economy by switching its Pyrex manufacturing process to automated machine pressing, thus enabling a reduction of retail prices by 30-50%.

Part of its high cost lay in the fact that, even though annual production numbered in the millions, the pieces were still individually blown by hand. The Great Depression in 1929 dealt Corning and Pyrex a great challenge. And, as cookware, albeit expensive for the times, Pyrex proved quite the success, selling over 4 million pieces its first four years of production and an additional 26 million over the following 8 years. With the Nonex formula altered to remove lead, work proceeded to develop a cookware line from it, which the company called Pyrex. In her experiments with it, she found that the foods cooked faster, at lower temperatures, with the added benefit that she could see the food as it cooked. When her ceramic casserole cracked, it was one of those battery jars, cut down to make a baking dish, that Corning researcher Jesse Littleton brought home for his wife to try. Nonex found success in other areas, however, including wet cell battery jars.

While the perfect answer to the railroads' breakage issue, it was ultimately unprofitable in that few of the new type globes required replacement thereafter. Corning Glass was engaged to come up with a solution, which they did in the form of a borosilicate non-expansion glass formula they dubbed Nonex. When hot, contact by rain or snow would cause them to crack.

The origins of Pyrex lay in a problem the early-20th century railroad industry faced with broken lantern globes.

Pyrex glass bowls