Free-to-shrink measurements

Obviously, the constrained-state and free-to-shrink measurements may give vastly different results depending on the orientation of the fiber. The melting point of drawn fibers measured in a constrained state is always higher than in the free-to-shrink measurements. It can be intuitively understood that in a constrained measurement, the entropy increase is smaller than in the free-to-shrink measurement, since in the constrained measurement the macromolecules are stretched, and they will remain partially stretched in the melt. They will lose their orientation in the melt, but that will require some time. Then, supposing that the heat of fusion is the same in both types of measurement (which is not always true, but can be accepted as a first approximation)... 

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