https://doi.org/10.1351/goldbook.12740
Highest-temperature or lowest-frequency relaxation in the loss curve of a polymer.
Notes:
- The \(\upalpha\)-relaxation is commonly related to cooperative conformational changes in macromolecules. These changes typically involve \(\pu{10\!-\! 20}\) main-chain atoms. For a polymer in a glassy state, the \(\upalpha\)-relaxation is characteristic of the glass transition.
- For some partially crystalline polymers, for example, polyethylene or polyoxymethylene, the \(\upalpha\)-relaxation originates from motions within the crystalline regions (the so-called "crystalline relaxation"). In such cases, the β-relaxation usually corresponds to the glass transition.