I just baked some fiberglass insulation in my outside electric oven.
Stripped some off normal house batting type, tossed it on a cookie sheet in the oven.
I baked it at 500-550F for awhile and it seemed fine, cranked it up to almost 600F and baked a longer time and the yellow color baked out, turned mostly grayish white, but the fiberglass itself seemed fine still.
I could not tell about any smells/fumes though. Being the stove is kept outside and was hauled in from a scrap yard where it had sat for awhile etc.. it stinks a bit in normal use anyway.
As far as bake time, subtract about 15 minutes from the time between these posts and that's about how long I baked it total. I lost track of the time, I was also sand blasting during that time, and also burned up my shop vac
SMOKED IT, bearing noise then WHOOF smoke everywhere. Junk thing was less than 6 weeks old and barely used at all!