These phthalocyanine blank CD-Rs lingered for years in unsealed JCs in an open cabinet in a room with daylight but no direct sunlight.
The UV light was filtered through 2 panes and scattered in the room and can only pass through the flanks of the JCs to the CD-R.
Or is the cause another, perhaps the oxygen of the air?
Originally, the label color was pictured like beside, which was kept in the dark.
In the case of the Kodak, the dye has disappeared into the outer most discolored 5 mm, so that the label print shines downwards.
The edge sealing of the CD-Rs is obviously alright.
The burning of such a CD-R leads to the write termination and the error rates increase even before the visible damaged area.
It should also be noted that the majority of stored CD-R in the cabinet has no such damage.
In addition, I had burned Lifetec (Aldi) CD-R from different manufacturers (AMS, Princo, Prodisc, Ritek) with clearcoat label coating, where the dye (and thus the data) was almost completely gone.