DSC (Differential Scanning Calorimetry) measures the temperature of the material as known quantities of heat are added to it. This behavior depends on absorbed moisture content which in turn is affected by whether or not the material is copper clad or not. DMA measures mechanical properties as the material's temperature is raised which do not so much depend on moisture content. Tim Reeves ECD -----Original Message----- From: Gerard O'Brien [mailto:[log in to unmask]] Sent: Thursday, September 20, 2001 8:23 AM Subject: Tg measurements by DMA When testing Tg with DSC, the TM-650 test method calls out for the test to be run with the copper clad still attached and that if removed to expect an 8 to 15 degree reduction in values. For DMA it does not reference testing with copper clad or removed. Can anyone give me the reason why? Regards Gerard O'Brien --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------