What information do you get from a differential scanning calorimetry plot?
Differential scanning calorimetry (DSC) is often used to study polymers. You heat a sample and a reference at the same rate. When the sample undergoes a phase transition, a different amount heat will flow to it than to the reference to maintain both at the same temperature. You plot the difference in heat flow as a function of temperature.
The melting of a solid is endothermic. The extra heat flow to maintain the temperature shows up as a peak on the DSC plot.
The top of the peak is the polymer's melting temperature,
When the sample crystallizes, less heat is required to raise the sample temperature. This shows up as a dip in the DSC plot.
The temperature at the lowest point of the dip is the polymer's crystallization temperature,
After a certain temperature, a polymer may undergo a glass transition. Its heat capacity increases. The middle of the slope represents the glass transition temperature,
A whole plot often looks something like this: