Magic-echo phase-encoding solid imaging of rubber materials below the glass transition temperature

NMR microimaging is a valuable tool for the investigation of the spatial distribution of material properties in elastomers, e.g., aging processes or cross-link-density inhomogeneities. However, such investigations have been restricted to temperatures far above the glass transition temperature, where the transverse relaxation times of elastomers are in the range of milliseconds. To extend these investigations to the temperature range below the glass transition temperature, the magic-echo phase-encoding solid imaging technique (MEPSI) has been applied. With MEPSI it was possible to investigate the spin-density and T (ind 1) distribution in a rubber sample at temperatures as low as 163 K. As an additional result it was found that the temperature dependence of the magic-echo amplitude could be used as an indicator for the glass transition.