Okay, so the rotation of evaporating black holes gives the universe its rotation, which leads to expansion - which itself both increases the rate of rotation & decreases the rate of expansion (but expansion is still continuous).
What happens in there has to be some chemical change in the universe for the phase transition to occur. It is indeed, expected to be a radiative process.
The rotation however, is even more intrinsic than that process. It is a part of the primordial dynamics. Like how spin is intrinsic to a particle without actual rotation, but this can also be argued to be the wrong model for particles. I can't be bothered going into that tonight, I'll do it another day.