photostability
Noun
Meaning
photostability (countable and uncountable, plural photostabilities)
(chemistry) stability against photochemical change
Examples
DBT improves the photostability of avobenzone by quenching the singlet oxygen produced from the triplet state of the keto form of avobenzone.
Clearly there is compelling interest in validating a method to determine the percentage of photo-protection that remains in a product after UV exposure, i.e., the photostability percentage.
Basically, if your sunscreen does not contain avobenzone, you probably don't have to worry about photostability.
This testing may be omitted if a scientific justification can be provided demonstrating that the product in the container closure proposed for market will not be susceptible to photostability effects.