The amorphous to crystalline phase change is of great interest for the production and operation of phase change memory and germanium electronic devices. Phase change memory relies on the ability to differentiate between differences in optical or electrical properties between the amorphous and crystalline phases of a single material. Amorphous germanium is useful both as a device component and as a precursor to flexible crystalline Ge films. The activation energy of crystal growth is a good proxy for the low temperature stability of amorphous films and can be calculated from a set of growth rates at different temperatures. Silver- and indium- doped antimony telluride (AIST) is phase change material commonly used in optical drives, like compact disks. In this study the crystallization rate of AIST was studied under isothermal conditions ranging from 130°C to 155°C. The growth fronts of individual grains were measured over time with an optical microscope. The activation energy for crystal growth was calculated to be 2.43 eV. The growth of crystal fronts in germanium films were observed with transmission electron microscopy. Ge films were crystallized at isothermal conditions from 520°C to 560°C with an in-situ TEM holder. The activation energy for crystal growth was calculated to be 4.08 eV. The data collected here is meant to serve as a companion to high temperature crystallization studies done with the same set of samples.