All I can suggest is measure it, then make he rounds to a few appliance retailers and measure the glass in current models. With luck you may find one that matches yours.

You could also take the measurements to a parts supply house and if you get a knowledgeable desk person who is customer oriented they might be able to help.

You could also try getting a piece cut. The problem here is that it would have to be extra thick to have the same strength as the tempered glass.
Also extra care would have to be taken with it, if it does break in the future it will splinter instead of shattering.