glazing could be a possiblity, but id say its probably wear on the brake pads, the reason it stops after the car is running for a little while is because the rotors warm up after the breaks are depressed a few times causing less friction, most likely the spring sensor may be worn thru and is now touching the rotor, the squealing that is normally associated with break wear is actually a built in sensor that lets u know when its time to check the pad and rotor wear, id say take it to a brake max or like company they all have free inspections and will tell u what u need (ie will measure ur rotors, check ur pads, check all the hardware etc...) brakes arent something u should ignore, a squeak is normal, a scream is a warning sign. good luck and have it checked out soon.