Warning message

Advance tickets required. Face coverings are required for all visitors, even if vaccinated. Learn more.

All About Glass

All About Glass

This is your resource for exploring various topics in glass: delve deeper with this collection of articles, multimedia, and virtual books all about glass. Content is frequently added to the area, so check back for new items. If you have a topic you'd like to see covered, send us your suggestion. If you have a specific question, Ask a Glass Question at our Rakow Research Library.

Annealing and Tension in Glass

Hot-working processes used to form a glass object—glassblowing for example—must be followed by a very gradual cooling period called annealing. See what happens when an object is not properly annealed and learn why it breaks.

Annealing Glass

If a hot glass object is cooled "too quickly," it may be strained at room temperature, and therefore may break easily. For small, or thin-walled shapes (particularly those made of glasses having low expansions) the effect may not be serious. For more massive pieces, the strain can be very