𝐺 ‡ = 𝜀 ‡ -𝓀 𝐵 𝑇 ln(𝜔(𝑇)) (26c) The second law of thermodynamics Finally, it is worthwhile to investigate if the obtained definitions of the thermodynamic quantities obey the second law of thermodynamics. As preparation, through derivation of Eq. 24d one finds that that the entropy of a system increases with its temperature, with constant heat capacity, according to Eq. 27b.