Volcanic Rock — Glas Transition, Crystallization, Melting
Natural materials such as rocks are difficult to analyze with regard to their chemical composition. Such materials are generally a mixture of different oxides, sulfates or carbonates. Volcanic rocks are generally solidified from molten magma and their main contents are different oxides. This example shows a DSC measurement result for such a material. It can clearly be seen that it solidified almost completely amorphous. The glass transition was between 623°C and 655°C. Cold crystallization and melting were detected at 884°C and 1111°C (peak temperature). The heat released during crystallization was comparable to the heat of fusion, indicating the highly amorphous nature of this mixture. (measurement with DSC 404 F1 Pegasus®)