Theoretic analysis and experimental evidence for relationships between the derivative thermogravimetric curves and the Gramm-Schmidt profiles

In the field of thermogravimetric analysis, the evolved gas analysis is a hyphenated technique which allows an easy and rapid identification of the gaseous products resulting from thermodegradation under non-isothermal conditions. In the present paper, the relationships between the Gramm-Schmidt profile (GS) and the DTG curve (dm/dt) will be theoretically analyzed. So, there are two curves which have the extreme points at the same time (temperature) values and which have complementary concavity and convexity. By complex parallel processes, the relationship is more complex from the mathematical point of view. The discussed theoretic cases are connected with the experimental data obtained through the thermal analysis of aminophenazone, glycyrrhetinic acid, amlodipine maleate, verapamil, and a technical polymethane.