Term: fatigue https://doi.org/10.1351/goldbook.FT07375 Definition: Loss of performance over time, due to chemical degradation. The major cause of fatigue is oxidation. Note: Although @P04589@ is a non-destructive process, side reactions can occur. Related Terms: 1) photochromism (http://doi.org/10.1351/goldbook.P04589). 2) oxidation (http://doi.org/10.1351/goldbook.O04362). Source: PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 338 (https://doi.org/10.1351/pac200779030293) Citation: 'fatigue' 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.FT07375 License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. Disclaimer: The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.