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RESEARCH PRODUCT
Molecular dynamics near the glass transition
K. Schmidt-rohrJ.h. MagillHans Wolfgang SpiessHans SillescuK. ZemkeK. Zemkesubject
Magic angleChemistryCarbon-13BiophysicsAnalytical chemistryCondensed Matter PhysicsSpectral lineNMR spectra databaseViscosityMolecular dynamicssymbols.namesakesymbolsPhysical and Theoretical Chemistryvan der Waals forceGlass transitionMolecular Biologydescription
Solid state 13C NMR spectroscopy has been applied to investigate the time scale and the geometry of rotational motions near the glass transition of the low-molar-mass van der Waals glass former 1,3,5-tri-α-naphthylbenzene (T g = 342 K). Two-dimensional 13C exchange spectra were taken between 347 and 372 K. With the principal values of the 13C chemical shift tensors determined from 13C CP/MAS spectra and static one-dimensional 13C spectra, the two-dimensional spectra are interpreted according to the isotropic rotational diffusional model to yield mean correlation times τ0 in the range 10 ms ˇ- τ0 ˇ- 50 s, and a log-Gaussian distribution of correlation times with a width of 1·5 decades. The mean correlation times agree with scaled viscosity data and with results from photon correlation spectroscopy.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1993-12-20 | Molecular Physics |