The one-dimensional symmetry and low linear density of fibers make them a special case for process-structure-property performance definition, simplified by the symmetry and complicated by meta-stable morphology and unwieldy sample geometry. The thermal analysis of fibers always reflects the total process history of the fiber, from synthesis through storage environment prior to sampling. Thermal analysis provides a convenient platform for quantifying fiber performance (or fabric performance) in terms of the fiber phase stability (DSC, DMA, TSC), dimensional stability (TMA), chemical stability (TGA, DSC) and mechanical property stability (DMA) as monitored under both prior history and end-use relevant conditions. Of special interest is the application of these techniques to the characterization of functional fibers, and fibers designed for in vivo use such that the resulting data is reflective of desired performance targets. (c) 2006 Elsevier B.V. All rights reserved.