This isn’t as simple as the subject may make it seem. The fact is that the change is drastic–from green to red, specifically.
I have a green votive candle that I’ve been burning for the past few days. I stuck a tea-light holder on the bottom of it, so now the remaining wax has pooled therein. Looking down on the melted wax, however, reveals a beautiful wine-red colour (through which I can see the bottom of the holder), rather than a deep green like I would expect. Why?
Cameleon candles and Spa candles use RGB LED clusters to effect color changes; not what you describe. Colorsine dyes, produced by United Polymer Technology LLC, are likely what you’re seeing in action. Here’s the patent:
Hmm, thank you. Unfortunately, it’s not quite like that. Only the pool of liquid wax displays this property (not heated or dripping wax), and in fact it’s clearly green if I swish it around on the sides of the container a little. I think what’s happening is something simpler, but I just can’t figure out what it would be.