Dipole-Echo Formation in Three-Pulse-Sequence NMR Experiments on Polymer Systems

Abstract

Data from three-pulse NMR experiments, namely, the Goldman-Shen pulse sequence and the stimulated-echo sequence, on partially crystallized poly(ethylene glycol) and tetrafunctional dimethylsiloxane networks are presented. A dipole echo has been observed after a third radiofrequency pulse. Quantum mechanical calculations of the response of the spin system to the three-pulse sequences have been performed, considering only thez-zcomponent of the dipole-dipole spin coupling. The resulting expression suggests dipole-echo formation and is in agreement with experimental data. © 1995.