Dynamic heterogeneity in supercooled ortho-terphenyl studied by multidimensional deuteron NMR
Institut für Physikalische Chemie, Johannes Gutenberg-Universität,
55099 Mainz, Germany
2 Fachbereich Physik der Universität Dortmund - 44221 Dortmund, Germany
Accepted: 19 August 1996
Using deuteron NMR, we have studied molecular reorientation rates and rate exchange processes in supercooled ortho-terphenyl. We monitor the re-equilibration of differently selected subensembles through four-time stimulated echo experiments. A comparison of the two-time with the four-time echoes suggests that the characteristic time scales for reorientation and dynamical exchange are relatively similar. The four-time correlation functions were described using various multi-state rate exchange models.
PACS: 64.70.Pf – Glass transitions / 76.60.Lz – Spin echoes / 05.40.+j – Fluctuation phenomena, random processes, and Brownian motion
© EDP Sciences, 1996