The present work of the Thesis has shown for the first time how the thermal glass transition of electrospun polymeric fibers can be studied by using the state-of-the-art Fast Differential Scanning Calorimeter. The potential of this technique to measure sample mass of the order of a few ng combining with the possibility to measure in situ involved heat events at rates up to 10^5K/s, make it a promising tool for the thermal characterization of these challenging samples. I developed a new deposition method that consists of electrospun fibers directly on the chip of the calorimetry, overcoming issues regarding the thermal contact or the handling of the sample. Furthermore, I have proposed and applied an original calorimetric approach aimed to get information about the glass transition and polymer dynamics while preserving the fibrous structure from melting.