Schramm, Sebastian ; Blochowicz, Thomas ; Gouirand, Emmanuel ; Wipf, Robert ; Stühn, Bernd ; Chushkin, Yuriy (2010)
Concentration fluctuations in a binary glass former investigated by X-ray photon correlation spectroscopy.
In: Journal of Chemical Physics, 132 (22)
doi: 10.1063/1.3431537
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
We investigate structure and dynamics of concentration fluctuations in the binary glass former methyl-tetrahydrofuran and oligomeric methyl metacrylate by photon correlation spectroscopy with partially coherent x-rays from a synchrotron source. Although the system is macroscopically well miscible and optically clear in the full temperature range, calorimetric and dielectric measurements reveal two distinct glass transition temperatures. The relaxation of long range concentration fluctuations turns out to be diffusive and exponential only well above the upper glass transition temperature. As the characteristic time τcf for concentration fluctuations shows a much weaker temperature dependence than the α-relaxation both traces finally intersect upon lowering the temperature. Thus, close to Tg, the concentration fluctuations show pronounced features of out-of-equilibrium dynamics such as compressed relaxation functions and a crossover to a ballistic wave vector dependence of τcf, like previously observed in various soft matter systems. Moreover, the analysis of time-resolved correlation functions reveals that the relaxation of concentration fluctuations around Tg involves pronounced dynamic heterogeneities.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2010 |
| Autor(en): | Schramm, Sebastian ; Blochowicz, Thomas ; Gouirand, Emmanuel ; Wipf, Robert ; Stühn, Bernd ; Chushkin, Yuriy |
| Art des Eintrags: | Bibliographie |
| Titel: | Concentration fluctuations in a binary glass former investigated by X-ray photon correlation spectroscopy |
| Sprache: | Englisch |
| Publikationsjahr: | 10 Juni 2010 |
| Verlag: | American Institute of Physics |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Journal of Chemical Physics |
| Jahrgang/Volume einer Zeitschrift: | 132 |
| (Heft-)Nummer: | 22 |
| DOI: | 10.1063/1.3431537 |
| URL / URN: | http://jcp.aip.org/jcpsa6/v132/i22/p224505_s1 |
| Kurzbeschreibung (Abstract): | We investigate structure and dynamics of concentration fluctuations in the binary glass former methyl-tetrahydrofuran and oligomeric methyl metacrylate by photon correlation spectroscopy with partially coherent x-rays from a synchrotron source. Although the system is macroscopically well miscible and optically clear in the full temperature range, calorimetric and dielectric measurements reveal two distinct glass transition temperatures. The relaxation of long range concentration fluctuations turns out to be diffusive and exponential only well above the upper glass transition temperature. As the characteristic time τcf for concentration fluctuations shows a much weaker temperature dependence than the α-relaxation both traces finally intersect upon lowering the temperature. Thus, close to Tg, the concentration fluctuations show pronounced features of out-of-equilibrium dynamics such as compressed relaxation functions and a crossover to a ballistic wave vector dependence of τcf, like previously observed in various soft matter systems. Moreover, the analysis of time-resolved correlation functions reveals that the relaxation of concentration fluctuations around Tg involves pronounced dynamic heterogeneities. |
| Zusätzliche Informationen: | Art.No.: 224505 |
| Fachbereich(e)/-gebiet(e): | 05 Fachbereich Physik 05 Fachbereich Physik > Institut für Festkörperphysik (2021 umbenannt in Institut für Physik Kondensierter Materie (IPKM)) 05 Fachbereich Physik > Institut für Festkörperphysik (2021 umbenannt in Institut für Physik Kondensierter Materie (IPKM)) > Struktur und Dynamik amorpher Systeme |
| Hinterlegungsdatum: | 15 Dez 2020 11:19 |
| Letzte Änderung: | 08 Jul 2021 07:16 |
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