“The tritium on my Rolex from the 1980s no longer glows in the dark.”
Tritium doesn’t glow. It is probably the phosphor material that has broken down. Although the tritium has gone through about 2.5 half-lives so its activity has been reduced to about 1/5 of the original. So maybe it glows but not so brightly?
ok.....the coating used to glow or show up in darkness but no longer at this point. Maybe it is so faint my older eyes can no longer detect anything.