I used a homemade "cold knife" to remove my rear glass. It was tough but with a little patience and a lot of grunting(or luck?), I got it out without damaging it.
I've attached a photo of a cold knife. It's what the pros use. You lay the blade down next to the glass and turn it so that it's inserted into the adhesive. After that, you grab the handle and pull while holding the shank of the glade upright.
I made mine by heating the blade of and old paring knife and putting a 90 degree bend in the first inch of it. I then drilled a hole in the handle near the blade and attached a stout piece of wire like a coathanger to pull on.
I've thought about it and I think if I were going to use a wire, I might try a "wound" guitar string. I think it would saw through the adhesive a lot easier than a smooth piece of music wire.
Just a couple of ideas...