Borosilicate Glass has excellent thermal shock resistance. It does not expand and contract like ordinary glass does when exposed to rapid changes in heat or cold. Unfortunately when Corning, Inc. sold off the PYREX® trademark it became pyrex® in America and the new company started using Soda-Lime Glass instead of Borosilicate Glass. The company that bought the PYREX® trademark for Europe continues to use Borosilicate Glass.