This research project, supported in the Analytical and Surface Chemistry Program, addresses the application of time-of-flight (TOF) mass spectrometry (MS) to the analytical characterization of polymers. During the tenure of this thirty-three month continuing grant, Professor Hercules and his students at Vanderbilt University will seek to establish definitive correlations between TOF secondary ion mass spectrometry (TOF-SIMS) fragmentation patterns and the molecular structures of well defined polymers and polymer blends. Additionally, they will apply matrix assisted laser desorption/ionization TOF MS (MALDI-TOF) to the analytical characterization of thick film (bulk) polymer analytes. The analytical characterization of polymers is a technologically important and challenging problem. Mass spectrometric techniques offer versatility and unparalleled sensitivity for a wide variety of polymer analytes. This research will enable TOF-SIMS and MALDI- TOF MS to be reliably used as analytical tools for the characterization of these ubiquitous materials. This research also has important implications for the broad field of materials degradation and stabilization.