Today I did an experiment with a new material in the laser. This is colored plate glass, like the kind used for making stained glass artwork. This didn't work at all in the laser. Let me explain what you're looking at here:
I set the laser to cut a 1 centimeter square near the edge of the piece. I have worked with glass before (using regular glass cutting tools) and I know that if you're gonna work from a large hunk of glass you never EVER do anything in the center of the pane unless you want it to break into a gazillion pieces.
I know glass can absorb a lot of heat, so I figured I'd need to get this pretty darn hot to cut through. I set the laser's power all the way to the top, and reduced cut speed so that it'd put a lot of heat into the glass. One pass at 100% power and 10% speed produced a blinding light during the cut, and a very shallow channel of bubbled glass. It seemed the glass was absorbing the heat, but I just didn't have enough power to make it through.
I decided to try a different approach- perhaps multiple passes at lower power would cut successively deeper? I tried this, and found the the bubbly glass in the channel simply re-formed in the wake of the beam, and didn't go any deeper with each pass. After a few times of this the glass simply got over-stressed and cracked, as you see in the picture.
I think it's pretty clear that my laser can't cut through glass like this.