  Superconductors like other solids cannot relax instantaneously from excited
states to thermodynamic equilibrium. In this paper, relaxation from thermal
excitations is investigated, like after absorption of radiation or, under
conductor movement, release and transformation of mechanical tension to thermal
energy. Relaxation proceeds within finite periods of time the length of which
increases the more strongly the closer the superconductor temperature has
already approached its critical value. Properties of many-particle systems (as
explained, by an analogy to nuclear physics), basic thermodynamic
considerations (temperature uniquely defined under solely equilibrium
condition) and standard, multi-component heat transfer principles (solid
conduction plus radiation in thin films) are applied as tools to prove this
expectation. Energy gap, superconductor critical current density and critical
temperature, as a result, are tightly related to relaxation rates and
relaxation times of the superconductor electron system. By numerical
simulations, an attempt is made to find a quantitative correlation of these
properties in a thin film superconductor.
