  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 pre-exponential 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.
