Kinetics of Processes Distributed in Activation Energy

Primak, William

doi:10.1103/physrev.100.1677

Cited by 379 publications

(85 citation statements)

References 5 publications

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“…This really was an important step for the study of disordered media. Then, in 1955, Primak [29] applied the Vand approach to kinetic orders larger than one, but he noted that one-order kinetics are most likely in solids. In 1960, Primak [30] goes on in studying the isochronous method.…”

Section: Modelingmentioning

confidence: 99%

Kinetics of Thermally Activated Physical Processes in Disordered Media

Poumellec

Lancry²

2015

Fibers

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Abstract:We describe a framework for modeling the writing and erasure of thermally-distributed activated processes that we can specifically apply to UV-induced refractive index change, particularly in fibers. From experimental measurements (isochrons and/or isotherms), this framework allows to find the distribution function of the activation energy by providing only a constant, which can be determined by a simple variable change when a few assumptions are fulfilled. From this modeling, it is possible to know the complete evolution in time of the system. It is also possible to determine the annealing conditions for extending a lifetime. This approach can also be used for other physical quantities, such as photodarkening, stress relaxation, and luminescence decay, provided that it can be described by a distribution function.

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Section: Modelingmentioning

confidence: 99%

Kinetics of Thermally Activated Physical Processes in Disordered Media

Poumellec

Lancry²

2015

Fibers

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“…Le blanchiment partiel de l'absorption induite, pour les grandes densités d'énergie, dans la fibre vierge révèle que certains centres Ge(1) sont convertis en espèces non-absorbantes même si la majorité des centres reste stable. Une large distribution de l'environnement des centres, due principalement au désordre de la matrice vitreuse, peut expliquer ce comportement [19][20][21].…”

Section: Uvx 2004unclassified

Étude des processus photochimiques primaires dans les fibres optiques germanosilicates lors d'une insolation ultraviolette

et al. 2005

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Résumé. Nous reportons des mesures d'absorption induite, dans le domaine spectral 360 nm-440 nm, dans les fibres germanosilicates hydrogénées ou non. Pour cela, nous avons mis au point une nouvelle technique de mesure de l'absorption induite mettant enévidence, contrairementà la technique de mesure classique, les processus primaires générés durant des temps d'insolation ultraviolette (uv) très courts (∼ms). Nos observations montrent que le centre Ge(1) est responsable de cette absorption dans les deux types de fibres.

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“…Consequently, we will consider that a superposition of independent microscopic processes with different activation energies contributes to the structural relaxation [1,10]. In the inset of Fig.…”

Section: Introductionmentioning

confidence: 99%

Structural relaxation kinetics for first- and second-order processes: Application to pure amorphous silicon

Roura

Farjas

2009

Acta Materialia

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The structural relaxation of amorphous materials is described as arising from the superposition of elementary processes with varying activation energies. We show that it is possible to obtain the kinetic parameters of these processes from differential scanning calorimetry experiments. The transformation rate is predicted for the transient decay when an isotherm is reached and for the relaxation threshold detected in partially relaxed samples.Good agreement is obtained with experiment if the individual components transform through first-order kinetics, but inconsistencies arise for second-order components. Our analysis, that improves the classical treatment by Gibbs et al. [1], allows the activation energies and the preexponential rate constants to be extracted independently. When applied to a-Si, we conclude that the pre-exponential rate constant is far from constant. The kinetic parameters obtained from DSC are used to analyze the relaxation of a-Si in pulsed laser experiments and to discuss the relationship between structural relaxation and crystallization.

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Kinetics of Processes Distributed in Activation Energy

Cited by 379 publications

References 5 publications

Kinetics of Thermally Activated Physical Processes in Disordered Media

Kinetics of Thermally Activated Physical Processes in Disordered Media

Étude des processus photochimiques primaires dans les fibres optiques germanosilicates lors d'une insolation ultraviolette

Structural relaxation kinetics for first- and second-order processes: Application to pure amorphous silicon

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