[Christ]

Henticules -

You can cut windshield (untempered) glass with a masonry wet saw, even with the plastic still installed. Score/snap works also, but you have to be pretty precise scoring both sides.

The glass needs to be heated to something over 1,300 degF. Pretty hot for an oven, unless you have a blast furnace or a forge pot.

At this temperature, the plastic will (obviously) melt and burn into soot and possibly less, leaving impurities and traces in the glass.

While I'm sure it would make for an interesting piece of art, I doubt it would fare well as a windshield.

Also, you'd have to keep the glass heated and bring the temperature down slowly. Cooling it too fast will cause it to crack and stress fracture, making it usable only as cullet for the next batch of glass to be made.

Glass can, however, be recycled endlessly, so have at it! You can't "waste" anything but time and fuel.