Thermodynamics of the glass transition

A thermodynamic analysis of the glass transition in polymers is presented, which predicts, with a minimum of assumptions, three of the four inequalities which have consistently been observed experimentally: i.e., that specific heat and isothermal compressibility of the glass are lower than those of the rubber, and that the Prigogine‐Defay ratio is larger than unity. The analysis cannot predict the fact that the thermal expansion coefficient of the glass is also lower than that of the rubber, and indeed the converse situation is not a thermodynamic impossibility.