Pyrex bowls

Do not buy the new stuff. Buy the old stuff!

The vast majority of glass products are made of soda-lime glass: window panes, jars, bottles, all kinds of glass. Soda-lime glass [is cheaper] to make than borosilicate glass, which is undoubtedly why Pyrex started experimenting with it. However, borosilicate glass is not only harder, stronger, and more durable than soda-lime glass; [it’s also more resilient to thermal shock. Thermal shock is what happens when a temperature change causes different parts of a material to expand at different rates, and the resultant stress can cause the material to crack. If the temperature change happens rapidly materials like glass can shatter or seem to explode.

PYREX is made with borosilicate glass. pyrex is made with soda lime glass.