Does Spraying printable discs shorten their life span?

I was wondering if anyone had any info on spraying discs could shortening their life span?

I bought some white inkjet printable DVD's and some printable silver CD's to use for some archiving.

I’d like them water resistant but not if some chemical reaction will turn them into coasters in a couple of months.

No. DVD’s are more or less impervious to chemicals due to being a plastic sandwich with the important stuff in the middle. That’s not to say you can’t ruin a disc with spray-on coatings, but the damage is immediate and caused by getting paint on the data-side of the disc, making it unreadable. So unless you’re putting something on there that can melt polycarbonate, there’s no worries.