The activation energy Delta H* for structural relaxation in the glass transition region can be determined from the heating rate dependence of the glass transition temperature T-g or the cooling rate dependence of the limiting fictive temperature T-f(v) measured using DSC or DTA. Delta H* values determined this way are in good agreement with the shear viscosity activation energies Delta H-eta*.Delta H-eta* for high T-g inorganic glasses can also be estimated from the width Delta(1/T-g) of the glass transition region measured by DSC or DTA using an empirical constant C = (Delta H-eta*/R)Delta(1/T-g). New data for sodium berate glasses yield values of the constant C in agreement with those from earlier studies.