Heat capacity spectroscopy HCS and differential scanning calorimetry DSC results are compared for eight polymers (especially for polyisobutylene (PIE) and a random copolymer of n-butyl methacrylate with 8% styrene) and glycerol. A mean value of the parameter a is obtained as (a) over bar = 4.3 +/- 2, where a = T over dot/delta T omega(max), with T over dot the DSC heating rate, delta T the temperature dispersion from the DSC transformation interval, and omega(max) the frequency of the imaginary part of maximum heat capacity, extrapolated from HCS to DSC temperatures. The results are discussed with regard to the fluctuation dominance of molecular glass transitions, to the fluctuation dissipation theorem, and to the Second Law of Thermodynamics. The a value seems to be universal, not depending on the substance group and fragility.