Title: Tammann’s 2/3rd rule
Long Title: IUPAC Gold Book - Tammann’s 2/3rd rule
DOI: 10.1351/goldbook.12806
Status: current

Definition
Empirical rule that states that in a partially crystalline polymer the glass-transition temperature can be reasonably approximated by a value equal to two-thirds of the melting temperature, \(T_{\rm{m}}\)/\(\pu{K}\).

Related Term
- melting temperature: https://goldbook.iupac.org//terms/view/12788

Source
- PAC, 2013, 85, 1017. 'Glossary of terms relating to thermal and thermomechanical properties of polymers (IUPAC Recommendations 2013)' on page 1039 (https://doi.org/10.1351/PAC-REC-12-03-02)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/12806/html
- json: https://goldbook.iupac.org/terms/view/12806/json
- xml: https://goldbook.iupac.org/terms/view/12806/xml

Citation: Citation: 'Tammann’s 2/3rd rule' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.12806
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Accessed: 2026-04-18T06:01:08+00:00