DSC calibration during cooling. A survey of possible compounds

A number of compounds is investigated for DSC calibration during cooling. A damantane and Zn show fast reversible transitions and can be applied both f or temperature and for heat calibrations. A third compound, namely 4,4'-azo xyanisole, has a liquid crystal to isotropic liquid transition at 409 K. Th is compound can be used for temperature calibration. Heat calibration with this compound is more problematic because of the small heat effect and the construction of the baseline. Other compounds like NaNO3, In, Hg and Pb, sh ow a slight supercooling. Nevertheless they can be used for heat calibratio n. The use of large samples of NaNO3 and In gives the possibility to constr uct the equilibrium onset temperatures of the cooling peaks, so these two c ompounds are also appropriate for temperature calibration on cooling.