Studies on the Method of Thermal Analysis of Organic Medicinals. III. Relations between Methods of Sample Preparation and Obtained Phase Diagrams

Three methods of sample preparation for the thermal analysis by the thaw-melt method were proposed. The heating procedure for solidification of the melt was proved to be very effective, especially for those samples that are apt to take vitreous states after fusion. Tests concerning both reliability and applicability the modified thaw-melt method were carried out on twelve kinds of organic binary system to which the application of the original method of Rheinboldt is thought to be difficult. The results indicate that the modified method is more accurate and reliable than the original one. The meaning and the use of the thaw point due to the metastable eutectic point in the system of compound formation were discussed.