UV photo reactive dye

Factual Questions
1

I’m looking for information on UV reactive dyes. I need something that gets dark when exposed to UV radiation and becomes clear again when the radiation is removed. Like the glasses that get dark when you go outside.

Even better is the dye described on this page: http://www.eblong.com/~zarf/review/review-12.html

"ShadowLands Clothing uses a photoreactive dye complex which darkens when exposed to light, and lightens again when the light decreases. The reaction has a wide dynamic range and is very fast – quick enough that no lag is visible as light conditions move across the cloth.
The result is carefully tuned so that, in daytime outdoor lighting, shadows simply do not show up on the fabric. Direct sunlight falls on darkened areas of the garment; shadowed areas are lighter; visually, the two surfaces are nearly identical. Some contrast remains, particularly in deep folds, but the effect is strikingly different from the normal human orientation of visual shadowing. The ShadowLands wearer seems to be standing in a pool of twilight amid broad day.

(This is not a fuligin darkness-of-the-void effect, mind you. ShadowLands comes in a range of colors, from white to brightly-colored mid-tones. The process has not yet been perfected for darker tones.)

ShadowLands designers are also selling a line of skinpaint which uses the same dye complex."

I can’t find any info on this stuff. Anyone here know anything about this? Please help this sorry student find info for hjs class project. I’ve hit a wall. I can’t find a single web site that gives a name or process or anything other than what I posted above.

2

Cooper blue is white when kept in the dark, but turns blue when exposed to UV. Googling on Photochromic turns up an assortment of other chemicals you might also be interested in.

3

The Shadowlands folk might be using some of these Water-Soluble Photochromic Spirooxazine Dyes.

4

Thanks a lot. I’ve been banging my head against this for two weeks.
I guess it’s all in knowing the right search terms, or knowing who to ask for the correct search terms. I should have come here days ago.

PHOTOCHROMIC is my word of the day and SQUINK is my hero of the day.

5

You wouldn’t be thinking about a certain prank using photo dyes that Robert Heinlein mentioned in Podkayne Of Mars, now would you?

It’s not a nice idea.

6

No idea what you’re talking about. I’m in an engineering based product development class (business school) and although we don’t need to actually build anything, the concept proposals have to at least be believable. I needed a photochromic chemical for our product to do what I wanted it to do.

You want to explain the prank or just leave me guessing?

7

In the book, a kid gets his hands on some photo dyes, & coats the faces of 2 sleeping people.

When they turn on the lights, the colored dyes–let’s just say the folks had to stay in their rooms for a long time.

Mix UV sensitive dyes right, & I suspect that they wouldn’t darken, except in daylight…you must admit, this is the stuff that classic pranks are made of. :slight_smile: