VOLUME EFFECT IN THE METASTABILITY OF CRYSTALLINE PHASES FORMED ON COOLING

The use of differential scanning calorimetry (DSC) to study the metastable break-down of chloroform 1,2-dichlorobenzene,o-xylene, cyclohexane and CCl 4 in various volumes at atmospheric pressure shows that when the smallest volumes ( mu m3) crystallise, metastable crystals which can be preserved, appear. The temperatures and enthalpies of transformation of these new phases have been determined and the experimental results allow hypotheses to be put forward concerning the order of appearance of the various phases.