Have you tried scraping it with a straight edge razer? On the back of the glass stove top cleaner I have it says right on there something to the effect of "if you have burnt or stuck on food that will not come off scrape with a straight edge razer". I use on all the time on it because I'm a rather messy cook :P.
I use Vim and an SOS pad...sometimes you still need to put a little elbow grease in, but it seems the only thing that works on my stove.
Iv tied all kinds of different things and nothing seems to work.
Easy off makes a cleaner that should get them off. Good luck!