Originally Posted by Ron W.
I thought they made the windows for the space shuttles form Pyrex.
First of all, pyrex is a brand name. It is used by the holder of the copyright of the name.
New pyrex cookware, from the World Kitchen company, is not the same chemical formulation as older pyrex cookware, from Corning Glass works. Corning sold the name in 1988.
Corning pyrex is borosilicate glass.
This is the glass in the big telescope at Mount Palomar, and the space-shuttle glass. (The pyrex is not the same as the white ceramic Corningware, which has lithium oxides.)
World Kitchen pyrex is soda-lime glass.
For details, here is the article from Wikipedia:
Pyrex - Wikipedia, the free encyclopedia
The question of whether the newer pyrex shatters more easily than the older version is, obviously, open to debate. However, the borosilicate glass of the older pyrex cookware was specifically formulated to be resistant to changes in temperature.