The reorientational motion of probe molecules in polymeric mesophases is studied by linear and non-linear electron spin resonance. A non-exponential decay of the orientational correlations, which is homogeneous for observation times longer than 10 mus, is found. In the undercooled phase of the polymer the apparent distribution of correlation times tau is extended over two decades. The temperature dependence of tau is well represented by a Vogel-Fulcher law and is consistent with the frequency-temperature superposition principle.
THE CHARACTERIZATION OF THE ORIENTATIONAL CORRELATION DECAY IN POLYMERIC FLUIDS BY LINEAR AND NONLINEAR ESR
ANDREOZZI, LAURA;GIORDANO, MARCO;LEPORINI, DINO
1994-01-01
Abstract
The reorientational motion of probe molecules in polymeric mesophases is studied by linear and non-linear electron spin resonance. A non-exponential decay of the orientational correlations, which is homogeneous for observation times longer than 10 mus, is found. In the undercooled phase of the polymer the apparent distribution of correlation times tau is extended over two decades. The temperature dependence of tau is well represented by a Vogel-Fulcher law and is consistent with the frequency-temperature superposition principle.File in questo prodotto:
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