The spectral density in simple organic glass formers: Comparison of dielectric and spin-lattice relaxation
- Publication type:
- Journal article
- Metadata:
-
- Abstract
- <jats:p>The spin-lattice relaxation time T1 of simple organic glass formers is analyzed by introducing a spectral density obtained from broadband dielectric susceptibility data χ″(ω). For this purpose χ″(ω) was measured for several glass formers, that do not exhibit a Johari-type secondary relaxation process, covering a frequency range between 10−2 Hz and 109 Hz at temperatures above and below the glass transition temperature Tg. We introduce an analytical function to fit the shape of the main relaxation (α-process) above Tg, in particular taking into account high-frequency contributions in χ″(ω) commonly known as high-frequency wing. Below Tg the latter feature appears as a power law susceptibility χ″(ω)∝ω−γ, with γ&lt;0.1 and a characteristic temperature dependence χ″(T)∝exp(T/const.), yielding almost 1/ω behavior in the spectral density. On the base of this complete description of χ″(ω), a quantitative comparison of dielectric and NMR spectroscopy is possible, which is carried out in full detail for glycerol-d3 (2H-NMR), yielding almost identical spectral densities at the Larmor frequency in both cases. In particular the temperature dependence of the high-frequency wing reappears in that of the spin lattice relaxation rate. In addition a semiquantitative analysis is given for trinaphthyl benzene (1H-NMR) and tricresyl phosphate (31P-NMR).</jats:p>
- Autoren
- T Blochowicz
- A Kudlik
- S Benkhof
- J Senker
- E Rössler
- G Hinze
- DOI
- 10.1063/1.479178
- eISSN
- 1089-7690
- ISSN
- 0021-9606
- Ausgabe der Veröffentlichung
- 24
- Zeitschrift
- The Journal of Chemical Physics
- Sprache
- en
- Paginierung
- 12011 - 12022
- Datum der Veröffentlichung
- 1999
- Status
- Published
- Herausgeber
- AIP Publishing
- Herausgeber URL
- http://dx.doi.org/10.1063/1.479178
- Datum der Datenerfassung
- 2024
- Titel
- The spectral density in simple organic glass formers: Comparison of dielectric and spin-lattice relaxation
- Ausgabe der Zeitschrift
- 110
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