material stability 

Synonym: stability
https://doi.org/10.1351/goldbook.08027
Constancy of a property of a material over time.
Notes:
  1. A material is said to be stable with respect to a specified property if its measured or examined property value does not fall outside a specified interval during storage under specified conditions over a specified period of time.
  2. A reference material is assessed for the stability of an embodied property under conditions of transport ("short-term stability") and storage ("long-term stability").
  3. The variation of the property value over time adds a contribution to the uncertainty budget or the examination uncertainty, as applicable. Regarding the assessment of stability of the reference material, detailed guidance is given in ISO Guide 35.
  4. The term "stability" is also used for stability of a measuring instrument or process (see control limit).
Source:
PAC, 2021, 93, 997. (Metrological and quality concepts in analytical chemistry (IUPAC Recommendations 2021)) on page 1009 [Terms] [Paper]