A series of chain-transfer agents used in reversible addition-fragmentation chain transfer/macromolecular architecture design by interchange of xanthates polymerizations were subjected to thermogravimetric analysis and gas chromatography/mass spectrometry to assess their stability to heat and to determine their degradation pathways. The effects of the chain-transfer-agent class and structure on the thermal stability are described. (c) 2006 Wiley Periodicals, Inc.