Morphological terms, information content

EPR is used extensively to detect, identify and follow the fate of radicals involved in polymerization or polymer degradation processes. It is also used extensively to characterize polymeric materials in terms of their morphology, heterogeneity, structural transformations, chain dynamics, and so on [2-5]. For this purpose, one can take advantage of the stable paramagnetic centers present in material to be examined (e.g., residual post-polymerization radicals, or TMIs used as catalytic centers or stabilizers). In most cases, however, external spin probes are added, including spin-labeled macromolecules (see Sections 23.2.1.5 and 23.2.2.1) [6]. The sensitivity and high content of structural information contained in the spin Hamiltonian parameters allow to obtain valuable - and often unique - data on the studied systems [7]. 

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