Sublimation enthalpy and vapour pressure measurements have been carried out in plastic crystals of the Neopentane serie having CH2OH group ( polyols ). Heat capacity determinations allow to compare the sublimation enthalpies , at the transition temperature of crystalline to plastic phase, with the values calculated by means of the group additivity method. From this comparison we have estimate a value of 18 kJ/mol for the OH hydrogen bond energy.