Strange light when burning

Ok just a minute ago I was burning some dark-blue electrick tape when I noticed that then burning (I have 2 lenses, one from a cheap red pointer, other from burner, diode is from 16x burner, i made a focus point about a 2 cm from aperture exit, dot is a 1mm or so),
when I noticed, that during excesive smoking (of tape of course) there are some strange light flashes, I thought it was just white smoke, maybe a spark or short flame from tape, but when I looked more closely, there is white and blu-violet light flashes from source of smoke!
I thought it has something to do with color of the tape, I burned a piece of black rubber, same thing happens!!
It's like... tiny, maybe half of 1mm sparks, but only white and blue-violet color, appearing randomly.

Anybody has any explanation?!

You can see that more clearly if you have protection goggles on. Here's the thread discussing that subject.

The sparks are the material getting heated white hot

But why does not the same thing happen when burning with an extremely focused green? :-? I've only noticed it with my red laser.