The relaxation of the specific heat and the entropy to their equilibrium
values is investigated numerically for the three-dimensional Coulomb glass at
very low temperatures. The long time relaxation follows a stretched exponential
function, f(t)=f0exp[−(t/τ)β], with the exponent β increasing
with the temperature. The relaxation time follows an Arrhenius behavior
divergence when T→0. A relation between the specific heat and the entropy
in the long time regime is found.Comment: 5 pages and 4 figure