Apart from chemical structure, thermal properties of polymers depend mainly on polymer morphology, which is affected by the processing conditions. Outdoor exposure of the materials leads to changes in polymer morphology. The main objective of this experimental investigation was to better understand the changes due to thermal transitions and the molecular organizations of the crosslinked EVA encapsulant material after aging in outdoor exposure. The thermal properties of unaged and aged EVA encapsulant material were measured by thermal analysis methods as TSC and DSC. For the aged EVA samples, the distinctive feature of these results is that there are two different endothermic processes due to the recrystallization phenomenon. Furthermore, the difference of the magnitude of peak current by TSC technique suggests increased crosslinking exposure occurring selectively in the high temperature phase as a result of outdoor exposure. (C) 2013 Elsevier Ltd. All rights reserved.