Irreversible and Reversible Melting

Equilibrium is reached for large crystals (/ - o°). The equilibrium melting is characterized by AG = 0. In the case of metastable crystals, zero entropy production melting occurs when they go to a melt of the same free enthalpy and degree of metastability (Agf = lajpl). Additional information can be obtained from Agt = Mii -T Ast, with Agt equal to AAAT/T°, where 

Superheating is a basic phenomenon that needs to be described using irreversible thermodynamics and can be examined by standard and temperature-modulated calorimetry. Superheating of crystals occurs if the heat conduction into or out of a sample is faster than the phase transition. 

Fast scanning calorimetry (FSC) is the future method that allows avoiding any crystallization or reorganiza- 

---