Relaxation is the process by which a material under consideration relieves the stress. alpha and beta relaxations and their significance depend on the nature of the material that we use for our study. In the case of semi-crystalline polymers, alpha relaxation is the melting and beta relaxation is the glass transition, while in the case of amorphous polymers alpha relaxation corresponds to the Tg while beta and gamma relaxations correspond to the crankshaft motion of the polymer chain segments (for epoxy resin beta relaxation is usually related to the relaxation of the glyceryl groups while the gamma relaxation is related to that of the methylene group motion. Hope this answers your query. If you need to know more there is a wonderful book "Thermal analysis of polymers fundamentals principles and applications" by Menzel and Prime.
Relaxation is the process by which a material under consideration relieves the stress. alpha and beta relaxations and their significance depend on the nature of the material that we use for our study. In the case of semi-crystalline polymers, alpha relaxation is the melting and beta relaxation is the glass transition, while in the case of amorphous polymers alpha relaxation corresponds to the Tg while beta and gamma relaxations correspond to the crankshaft motion of the polymer chain segments (for epoxy resin beta relaxation is usually related to the relaxation of the glyceryl groups while the gamma relaxation is related to that of the methylene group motion. Hope this answers your query. If you need to know more there is a wonderful book "Thermal analysis of polymers fundamentals principles and applications" by Menzel and Prime.
Alpha relaxation is generally associate with the motion of 50-100 carbon atoms and their substituent groups about the chain axis whereas secondary relaxations i.e. beta transitions are related to movements of few carbon atoms (
α relaxation (slow relaxation process usually occurs above glass transition temperature of material) is related to the cooperative motion of molecules, thus activation energy would be related to the translation of molecules through the medium.
In case of β and γ relaxation (faster relaxation process occurs below glass transition temperature), the activation energy usually describes the process of change of conformation (structure shape) of molecule.
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