I've wouldn't think on a steel rotor with not even 100kg of weight at 30mph tops you could cause a rotor to glow. F1 brakes glow as there carbon/ceramic?? they run hotter temps and the actual materials boiling point is lower. FIA GT cars run iron discs and never glow even though they can reach hundreds of degrees. As far as I know anyway...

I read too that to bed in the brakes properly you should do some hard stops then pour water over them to cool, then repeat. Supposed to do something to the surface?