TITLE

Evolution of the dynamic susceptibility in molecular glass formers: Results from light scattering, dielectric spectroscopy, and NMR

AUTHOR(S)
Petzold, N.; Schmidtke, B.; Kahlau, R.; Bock, D.; Meier, R.; Micko, B.; Kruk, D.; Rössler, E. A.
PUB. DATE
March 2013
SOURCE
Journal of Chemical Physics;Mar2013, Vol. 138 Issue 12, p12A510
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Although broadly studied, molecular glass formers are not well investigated above their melting point. Correlation times down to 10-12 s are easily accessible when studying low-Tg systems by depolarized light scattering, employing a tandem-Fabry-Perot interferometer and a double monochromator. When combining these techniques with state-of-the-art photon correlation spectroscopy (PCS), broad band susceptibility spectra become accessible which can compete with those of dielectric spectroscopy (DS). Comparing the results with those from DS, optical Kerr effect, and NMR, we describe the evolution of the susceptibilities starting from the boiling point Tb down to Tg, i.e., from simple liquid to glassy dynamics. Special attention is given to the emergence of the excess wing contribution which is also probed by PCS and which signals a crossover of the spectral evolution. The process is attributed to a small-angle precursor process of the α-relaxation, and the apparent probe dependent stretching of the α-process is explained by a probe dependent contribution of the excess wing. Upon cooling, its emergence is linked to a strong decrease of the strength of the fast dynamics which is taken as reorientational analog of the anomaly of the Debye-Waller factor. Many glass formers show in addition a slow β-process which manifests itself rather universally in NMR, in DS, however, with different amplitudes, but not at all in PCS experiments. Finally, a three-parameter function is discussed interpolating τα(T) from Tb to Tg by connecting high- and low-temperature dynamics.
ACCESSION #
86446757

 

Related Articles

  • Light scattering study on the glass former o-terphenyl. Petzold, N.; Rössler, E. A. // Journal of Chemical Physics;9/28/2010, Vol. 133 Issue 12, p124512 

    Combining double monochromator, tandem Fabry-Pérot interferometry (TFPI), and photon correlation spectroscopy (PCS), the full range of the dynamic susceptibility of the glass former o-terphenyl is covered (240-440 K). A time resolution of 6 ns is reached by the PCS setup, and the measuring...

  • Investigation of orientational correlations and structural transitions in neat liquids. Rozhdestvenskaya, N. B.; Smirnova, L. V. // Journal of Chemical Physics;7/15/1991, Vol. 95 Issue 2, p1223 

    The temperature dependence of depolarized light scattering intensity (DLSI) and nuclear magnetic resonance (NMR) chemical shift were measured for hexafluorobenzene in the temperature range from 10 to 63 °C. The DLSI curve is not monotone, consists of regions of different slope, and has a dip...

  • Multiple Light Scattering Probes of Soft Materials. Scheffold, Frank // AIP Conference Proceedings;2007, Vol. 885 Issue 1, p135 

    I will discuss both static and dynamic properties of diffuse waves. In practical applications the optical properties of colloidal systems play an important role, for example in commercial products such as sunscreen lotions, food (drinks), coatings but also in medicine for example in cataract...

  • Dynamics of colloid silver nanoparticles in an evaporating water drop. Myslitskaya, N.; Khitrin, A.; Ivanov, A.; Samusev, I.; Bryukhanov, V. // Russian Physics Journal;Apr2012, Vol. 54 Issue 11, p1280 

    The method of photon correlation spectroscopy is used to investigate the distribution of the diffusion coefficient of silver nanoparticles in an evaporating water drop given that the drop base area remains unchanged (the pinning condition). It is established that the capillary flow dominates...

  • An investigation of a sol-gel/melt transition: The poly(ethylene oxide)/methanol/LiClO4 system. Peng, Shufu; Bogoslovov, R.; Piet, G.; Selser, J. C. // Journal of Chemical Physics;5/8/2004, Vol. 120 Issue 18, p8841 

    The crossover behavior of 50 000 molar mass poly(ethylene oxide)/methanol solutions from dilute solution to the melt/gel was examined. At first this behavior was investigated without LiClO4 and then reexamined with LiClO4. To better understand this behavior, the dependencies of dynamic light...

  • Nanoparticle tracking system analyzes polydispersed samples. Carr, Bob // Laser Focus World;Nov2008, Vol. 44 Issue 11, p83 

    The article provides information on the analysis of nanoparticles. It is stated that the ability to view nanoparticles directly and individually allows a nanoparticle tracking analysis system to study polydispersed samples with particles of different sizes and shapes. Dynamic light scattering...

  • High-resolution dynamic light scattering using a software correlator with analog detection. Wang, Gang; Xue, Yan; Kang, Zhi-Hui; Jiang, Yun; Zhao, Zhi-Sheng; Gao, Jin-Yue // Review of Scientific Instruments;Aug2006, Vol. 77 Issue 8, p086102 

    In this article, a dynamic light scattering (DLS) experimental system with 12.5 ns time resolution has been realized based on the use of a photomultiplier tube, a virtual digital storage oscilloscope module, and a personal computer. This experimental system is designed to work on analog...

  • Assessing the network connectivity of modifier ions in metaphosphate glass melts: A dynamic light scattering study of Na-Zn mixtures. Sidebottom, D. L.; Vu, D. // Journal of Chemical Physics;2016, Vol. 145 Issue 16, p164503-1 

    Photon correlation spectroscopy conducted on polymeric metaphosphate melts [NaPO3]1-y [Zn(PO3)2]y shows a systematic decrease in glass fragility as the more strongly bonding Zn cation replaces the more weakly bonding Na cation as a crosslinking agent between PO3 chains. This decrease is similar...

  • 2-Bromophenyl Salicylate. Thompson, Donovan; Mitchell, Sierra; Clarke, Kevin; Sarden, Kerry; Aiken, Karelle S. // Molbank;Dec2012, Vol. 12 Issue 4, p1 

    2-Bromophenyl salicylate is synthesized from 2-benzyloxybenzoic acid in two steps. The final compound has been characterized by IR, 1H-NMR, 13C-NMR and HRMS. The melting point for 2-bromophenyl salicylate is provided.

Share

Read the Article

Courtesy of VIRGINIA BEACH PUBLIC LIBRARY AND SYSTEM

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics