Solid-state H-1 NMR relaxometry studies were conducted on a hydroxy-terminated polybutadiene (HTPB) based polyurethane elastomer thermo-oxidatively aged at 80 degrees C. The H-1 T-1, T-2, and T-1p relaxation times of samples thermally aged for various periods of time were determined as a function of NMR measurement temperature. The response of each measurement was calculated from a best-fit linear function of the relaxation time vs. aging time. It was found that the T-2,T-H and T-1p,(H) relaxation times exhibited the largest response to thermal degradation, whereas T-1,T-H showed minimal change. All of the NMR relaxation measurements on solid samples showed significantly less sensitivity to thermal aging than the T-2,T-H relaxation times of solvent-swollen samples. (c) 2005 Elsevier Ltd. All rights reserved.