From: https://www.uttbio.com/wp-content/up...Cannabinol.pdfCBN is formed from degradation of THC on exposure to heat and UV light, and this conversion occurs over time-subject to storage conditions.
Exposure to light (not direct sunlight) was shown to be the greatest single factor in loss of cannabinoids especially in solutions, which should therefore be protected from light during analytical and phytochemical operations.