Activation energy spectrum (AES) model

E. Illekova et al.: Mater. Sci. Eng. B22 (1994) 181.

Procedure:

Isothermal measuring regime
Several measurements at various temperatures T_a

Activation energy ΔE ^*_AES(T_a,t_a) (kinetic parameter) and h_T,Ta,ta(ΔE^*_AES) (distribution function) could be determined:

ΔE^*_AES(T_a,t_a) = RT_aln(υ₀t_a)

h_T,Ta,ta(ΔE^*_AES) = -1/(RT_a).d[ΔH_{excess,T,Ta,ta}(t)]/d(lnt)

both h_T,Ta,ta(ΔE^*_AES) and ΔE^*_AES(T_a,t_a) can be predicted by the DNLR model

Model assumes:

First order kinetics

An unknown spectrum of independent relaxation processes, g(ΔE^*_AES,j)

Constant two-parameter relaxation times τ_j(T) = A_AESexp[ΔE^*_AES,j/(RT)]

Complete separation of three forms of structural relaxation phenomena (irreversible relaxation exotherm, anneal-induced relaxation endotherms, glass transformation effect)

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