Light scattering and dielectric studies on glass forming liquids

E.W. Fischer

Physica A: Statistical Mechanics and its Applications, 1993, vol. 201, issue 1, 183-206

Abstract: The α-relaxation behaviour of polymers and glass forming viscous liquids is well described by the Vogel-Fulcher-Tammann equation, introducing a Vogel temperature T0 at which the relaxation time τα diverges (T0 ≈ Tg - 50 K). With the recent development of the mode coupling theory a new critical temperature Tc is introduced located about 50 to 80 K above Tg. The relevance of the various temperatures is discussed on the basis of dynamic light scattering studies and dielectric relaxation data. The dynamic and static light scattering experiments revealed some unexpected features, which cannot be explained on the basis of conventional liquid state theories: (1) In static light scattering the intensity I(q→0) is no longer proportional to the isothermal compressibility. (2) This excess scattering Iexc shows a strong q-dependence (q = (4πn/λ)sin(θ/2)) corresponding to a correlation length ξ in the range of 20–200 nm. (3) The Landau-Placzek ratio IRayleigh/2IBrillouin is much too high, compared with the results of light scattering theories. (4) In photon correlation spectroscopy a new ultraslow hydrodynamic mode (Γ∼q2) is detected with relaxation rates Γ about 10-4 to 10-7 lower than those of the α-process at a given temperature.

Date: 1993
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/0378437193904162
Full text for ScienceDirect subscribers only. Journal offers the option of making the article available online on Science direct for a fee of $3,000

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:phsmap:v:201:y:1993:i:1:p:183-206

DOI: 10.1016/0378-4371(93)90416-2

Access Statistics for this article

Physica A: Statistical Mechanics and its Applications is currently edited by K. A. Dawson, J. O. Indekeu, H.E. Stanley and C. Tsallis

More articles in Physica A: Statistical Mechanics and its Applications from Elsevier
Bibliographic data for series maintained by Catherine Liu ().