I was curious about Sean Penn's neon-colored wardrobe and wanted to make sure this was actually a historical anomaly for the time presented or if maybe I just wasn't aware of neon clothing in the 1930s.
https://thekit.ca/style/clothing/history-of-neon-clothing/
From what I can find, it looks like while neon SIGNS were in existence at the time, there's no evidence that neon or fluorescent colored clothing ever existed before the 1960s at the earliest, and of course it was not widely popular until the 80s.