A Phenomenological Description of the PALS Response in Glass - Forming Systems

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A phenomenological description of the ortho-positronium (o-Ps) response from positron annihilation spectroscopy (PALS) and the dynamics from viscosity studies on two typical glass-forming compounds within the framework of the two-order parameter (TOP) model is presented. The dynamical data are accounted for by the modified Vogel – Fulcher – Tamman - Hesse (M-VFTH) equation. Subsequently, the quasi-sigmoidal course of the o-Ps lifetime, τ3, with or without the high-temperature plateau region as a function of the temperature over a wide temperature range can be described by an effective free volume version of the TOP model. This simultaneous description suggests a close relationship between the PALS response and the dynamics of supercooled liquids and seems to support the liquid - like and solid - like domain physical picture of all the three physical states of the disordered phase of the condensed systems.

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Periodical:

Edited by:

S. J. Wang, Z. Q. Chen, B. Wang and Y. C. Jean

Pages:

48-52

DOI:

10.4028/www.scientific.net/MSF.607.48

Citation:

J. Bartoš "A Phenomenological Description of the PALS Response in Glass - Forming Systems", Materials Science Forum, Vol. 607, pp. 48-52, 2009

Online since:

November 2008

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$35.00

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