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Journal ArticleDOI

Detailed comparison of the Williams–Watts and Cole–Davidson functions

C. P. Lindsey, +1 more
- 01 Oct 1980 - 
- Vol. 73, Iss: 7, pp 3348-3357
TLDR
In this paper, the distribution function of relaxation times underlying the nonexponential relaxation function of Williams and Watts is derived and compared with the analogous Cole-Davidson distribution function, and several useful relations between relaxation and distribution functions are summarized or derived, and the limitations of deriving distribution functions from relaxation functions are discussed.
Abstract
The distribution function of relaxation times underlying the nonexponential relaxation function of Williams and Watts is derived and compared with the analogous Cole–Davidson distribution function. In order to make the comparison between the two distribution functions, a simple empirical relationship between the Cole–Davidson and Williams–Watts parameters was determined which may be used to compare data analyzed using the two fitting functions. Although the relaxation functions are similar to each other, the distribution functions are quite dissimilar. The Cole–Davidson distribution shows a sharp long time cutoff, while the Williams–Watts distribution decays approximately exponentially at long times. Finally, several useful relations between relaxation and distribution functions are summarized or derived, and the limitations of deriving distribution functions from relaxation functions are discussed.

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Citations
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Journal ArticleDOI

Fragility and low temperature excess specific heat in polymer electrolytes

TL;DR: In this paper, the mechanical properties and the low temperature specific heat have been measured in a class of polymer electrolytes based on complexes of poly(ethylene) oxide (PEO) and sodium metal salts.
Book ChapterDOI

Dynamic Light Scattering in Bulk Polymers

TL;DR: In this paper, the types of fluctuations that occur in polymers and their manifestation in the light scattering are presented and the features which are characteristic of polymers are elucidated as well as the general behavior of light scattering from liquids and amorphous solids.
Journal ArticleDOI

Light and Neutron Scattering Complex Relaxation Behaviour in Glass Forming Liquids from Brillouin Scattering

TL;DR: In this paper, the authors focus on inorganic network glassformers and analyze the effect of α-and β-relaxation processes on LA Brillouin lines. But the analysis is based on viscoelastic theory for density fluctuations.
Journal ArticleDOI

Kinetics of the glass transition of fragile soft colloidal suspensions

TL;DR: The fragility parameter D, which signifies the deviation from Arrhenius behavior, is obtained from fits to the time evolutions of the structural relaxation time scales and corroborates the behavior of fragility in molecular glass formers with respect to equivalent variables.
References
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Journal ArticleDOI

Dispersion and Absorption in Dielectrics I. Alternating Current Characteristics

TL;DR: In this paper, the locus of the dielectric constant in the complex plane was defined to be a circular arc with end points on the axis of reals and center below this axis.
Journal ArticleDOI

Non-symmetrical dielectric relaxation behaviour arising from a simple empirical decay function

TL;DR: In this article, the empirical dielectric decay function γ(t)= exp −(t/τ 0)β was transformed analytically to give the frequency dependent complex dielectrics constant if β is chosen to be 0.50 in the range log(ωτ0) > −0.5.
Journal ArticleDOI

Analysis of Structural Relaxation in Glass Using Rate Heating Data

TL;DR: In this paper, a method was developed to determine the kinetic parameters controlling structural relaxation in the glass transition region from data acquired during continuous heating or cooling, where the data were linearized using the method of Narayanaswamy, and the continuous temperature variation during heating and cooling was dealt with by invoking the superposition principle.
Journal ArticleDOI

Further considerations of non symmetrical dielectric relaxation behaviour arising from a simple empirical decay function

TL;DR: The empirical dielectric decay function ϕ(t)= exp −(t/τ0)β, 0 0, but significant corrections may have to be applied for β > 0.5 and log ωτ0 < 0.
Journal ArticleDOI

On the numerical inversion of the Laplace transform and similar Fredholm integral equations of the first kind

J G McWhirter, +1 more
- 01 Sep 1978 - 
TL;DR: In this article, the Laplace transform and other dilationally invariant integral equations of the first kind were derived for the eigenfunctions and eigenvalues, and the maximum possible amount of information was obtained when solving the inverse problem numerically.
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