Temperature-modulated DSC (TM-DSC) is a tool generally employed for low-temperature applications on polymers. The STA 449 F1 Jupiter® and DSC 404 F1 Pegasus® are the first instruments capable of doing temperature modulation at high temperatures. Presented here are measurement results for mineral fiber insulation. In the total DSC curve, relaxation, oxidation and glass transition are overlapped. The glass transition can only be precisely analyzed by using the reversing part of the TM-DSC curve.