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-1-
Theoretical Proof of the Standard WLF Equation in the
Glass Transition
Wu Jialin
College of Material Science and Engineering, Donghua University, Shanghai, PRC (200051)
E-mail:jlwu@dhu.edu.cn
Abstract
The random first-order
transition theory has been directly proved by the theoretical proof for the
standard WLF equation, based on the intrinsic 8 orders of instant 2-D mosaic geometric structures, in
the glass transition. The theoretical proof shows that the constant c
1
in the WLF equation, taking
logarithm, is the non-dimension activity energy to break solid-lattice, and c
2
k the potential well energy.
The Clapeyron equation governing the first order phase transition in thermodynamics only holds true in
subsystem, instead of system. The many-times repeated application of the first order phase transition
law on subsystems will result in the glass transition and the singularity. The theoretical proof shows
that the mode of glass transition is slow inverse cascade, to break solid domain, and fast cascade, to
relax stress, of excited interface energy flow in local zone, and the glass transition is an emergent
behavior of the subsystems of system. The subsystem here is a percolation caused by the connections
of excited interface energy flow in time and in space in the glass transition.
Keywords: Glass transition, WLF equation, Mosaic geometric structure, Percolation, Random first
order transition
1. Introduction
Glass transition theory is an important subject in condensed-matter physics [1]. There is the
well-known semi-empirical Willams-Landel-Ferry (WLF) equation [2]
()
6.51
44.17
log
2
1
+−
−
−=
+−
−
−=
g
g
g
g
g
TT
TT
CTT
TTC
T
η
η
In which c
1
and c
2
are two constants for most flexible polymer. Theorists have been trying to prove
this time-temperature equivalent equation directly from fundamental theories of the glass
transition and to understand the physical meaning of the two constants. In the previous papers [3,
4, 5], a more fundamental model of the intrinsic 8 orders of instant 2-D mosaic geometric
structures in glass transition has been proposed. This model provides a universal picture, from T
g
to T
m
, of particle- clusters cooperative migration in one direction in the ideal solid-to-liquid glass
transition. It can be simply described as that in a reference particle a
0
3-D z-component local space,
all the 320 interface excitations, categorized into 8 orders, and appearing one by one on the 8
orders of instant 2-D mosaic lattices formed by 200 particles in z-component, step by step and
from fast to slow induce 136 particles (here, it is unnecessary to bring in the concept of correlation
length, instead, the number of cooperative migration particles can be obtained directly by
geometry method [3]) to move back and forth to thaw a solid-domain along local ±z-axial. Once
the 320-th interface excitation appears, the +z-axial a
0
particle immediately migrates just one
particle-distance away from its 4 neighboring -z-axial particles and gives rise to 5 z-axial
particle-cavities. As for the subsequent a
0
particle on the other arbitrary z’-component space, the
same process will occur. Only after a long time and repetitious rearrangements has the reference
a
0
particle fully re-coupled with its primal 4 neighboring particles. The motion mode in the glass
transition is the slow orientation process in inverse-cascade to thaw solid domain structure and the
fast re-orientation process in cascade vibrant to relax orientation entropy stress and rebuild local
structure.