Doug

Many dyes fade under intense UV (and even not so intense), so why should
a fluorescent one be any different? I do not know a darn thing about dye
chemistry, but fading must involve a molecular change, so we are looking
at photosensitivity. I suggest that "photons" may be knocking the
bejabers out of the looser bonds within the molecule. Interestingly,
what happens to these molecules and the bits knocked off? Do they
influence the acrylic molecules, mechanically or electrically? Maybe you
need to ask the makers???

Brian

Douglas Pauls wrote:
>
> Good morning all,
> I had a question come in this morning from one of our satellite assembly
> sites regarding the fluorescent nature of acrylic coating.  We use Humiseal
> 1B31 on most of our products, and 1B31 contains a fluorescent dye marker so
> that it is easy to see under black light.  We also have a machine that
> erases UV-erasable EEPROMs.  That UV exposure is usually at a higher power
> level than the simple black light used for inspection.  After 4-5 exposures
> to that intense UV light, the 1B31 seems to lose its fluorescent
> characteristics.  The film is still present and appears to be intact, but
> does not glow under black light.
>
> My question, can UV dye markers "wear out" under intense UV light?
>
> Doug Pauls
> Rockwell Collins
>
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