Differential Scanning Calorimetry, DSC(macrogalleria), (instrument above) is used to measure the heat absorption or emission from a specimen as its temperature is raised.  It is a valuable technique in determining the Tg of a matrix and the degree of crystallinity of the matrix.  In composite materials, the polymers closely in contact with the fibers can display a different Tg and degree of order due to the interaction with fibers and the presence of an interphase.  DSC can be used qualitatively determine what is occurring at an interphase.  The technique can also measure residual cure in cured laminates.  Heat given off during any additional cure will appear as an exothermic peak that occurs after Tg.  However, reliable comparisons of residual cure heat are difficult because large variations in fiber content can occur in very small samples.  Below is a typical DSC thermogram for a semicrystalline polymer.

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