I've tried many times, and could NEVER make glass craze under any circumstances other that spraying water on hot glass. Rapid heating does NOT cause crazing, no matter what kind of glass is involved. After many experiments, I published my results in the peer-reviewed Journal of Forensic Sciences. You can download a copy here:

[www.firescientist.com]

Click on "Behavior of Glass at Elevated Temperatures"

This is one myth that was capable of being absolutely disproved by a laboratory experiment, but last month at EKU, we made some crazed glass with fog from a fire hose on a hot window in a test fire. You may be able to see this in a week or 2 (May 7 or may 14) when ABC's 20/20 does an hour long show on fire investigation.

John Lentini, CFI, D-ABC
Fire Investigation Consultant
Florida Keys
[www.firescientist.com]