Scanning microcalorimetry (sometimes called HSDSC for "High Sensitivity DSC") can often reveal subtle thermal transitions that cannot be detected using traditional DSC.
In the example shown here a very small endotherm at -25 C was detected as the sample was cooled to -45 C at .2 C/min. An exotherm was detected slightly above this temperature during heating. Two cooling and heating cycles were performed and the lack of reproducibility indicates the transitions were not completely reversible. Detection of low levels of order/disorder can be critical to ensure lyophilized samples do not collapse during storage.