  The excess heat capacity at glass transition temperature in two types of
glass-forming systems of [xNaNO3\cdot(1-x)KNO3]60[Ca(NO3)2]40 (0 \leq x \leq 1)
and Ca(NO3)2\cdotyH2O (4 \leq y \leq 13) is studied. In the former system, with
the replacement of K+ cation with Na+ cation, the excess heat capacity is
almost invariable around 65.1 J\cdotmol-1\cdotK-1, while the excess increases
by 38.9 J\cdotmol-1\cdotK-1 with the increasing per molar H2O content in latter
system. A quantitative description of the excess heat capacity is built up with
the consideration of atomic and molecular translational motion in the
glass-forming systems. This finding might offer further understanding to the
glass transition.
