Hi all,
We have had similar troubles in the past with coplin jars cracking 
at high temperatures. We have now solved this by obtaining 
Borosilicate coplin jars which will withstand temperatures up to 
approx 110 degrees celcius. They are a lot more expensive but are 
cheaper in the long run because we don't crack them anymore. 
This may not be any help to people in the U.S. but we bought ours 
from a company called 
Lomb Scientific
SD2131900 (code for coplin jar)
Ph: 61 2 8536222
Fax 61 1300303025


Rosalba Zumbo
Technical Officer ( Scientific)
Institute of Forensic Medicine
Sydney, Australia
Fax 61 2 95664573