I still don't think they could be hot enough, or the contact be long enough, for anything to glow like that, especially if it had a decent amount of thickness to it. But of course, I'm no scientist. :p
I'm, not trying to shoot down ideas or anything, it's just something I've thought of before, even years ago. The question of 'how hot is a lightsaber supposed to be?' I bet LFL made some sort of article about it somewhere. Haha.