TGA measures the change in the mass of a sample over time during temperature changes. This can provide useful information about many physical phenomena such as phase transitions, absorption, adsorption and desorption; as well as chemical phenomena such as thermal decomposition or solid-gas reactions.
DSC measures the heat flow to and from the sample over time during temperature changes. This allows for the identification of exo- and endothermic phenomena such as melting, crystallisation, glass transitions and also provides information about a materials specific heat capacity and heats of reaction.