The thermo-mechanical response of single crystals has been studied in detail since the discovery of X-ray and electron diffraction. While an extensive knowledge exists on the effect of crystallographic orientation on deformation and recrystallization behavior of single crystals, the thermo-mechanical response of grains of different orientations embedded in a polycrystalline matrix are not well understood. With the emergence of microstructure based models predicting the structure evolution during deformation or recrystallization, data validating the predicted structure changes are essential. This requires to study the evolution of microstructural attributes such as morphology or orientation of an individual grain within a specific grain neighborhood during mechanical or thermal exposure. Interrupted coupon scale testing, with a separation of testing and microstructural observation is not sufficient due to the small size of the objects to be observed. Thus, the structure evolution of selected grains has to be followed in-situ.