beta relaxation

synonym: β-relaxation
https://doi.org/10.1351/goldbook.12744
Second-highest-temperature or second-lowest-frequency relaxation in the loss curve of a polymer.
Notes:
  1. For an amorphous polymer, the \(\upbeta\)-relaxation is generally related to localised motions involving only a few atoms of a polymer chain or is due to side-group motion.
  2. In some partially crystalline polymers, the \(\upbeta\)-relaxation corresponds to the glass-transition temperature (see Note 2 of definition alpha relaxation).
Source:
PAC, 2013, 85, 1017. (Glossary of terms relating to thermal and thermomechanical properties of polymers (IUPAC Recommendations 2013)) on page 1019 [Terms] [Paper]
Citation: 'beta relaxation' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.12744 RIS BibTex EndNote
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