Really depends on what is being used as the polyurethane thinner.  If they are using toluene for quicker setting, I have seen the Nitrile gloves start to soften and get sticky.  The Xylene is not quite as volatile and I have not seen any softening.  I have used toluene to thin acrylated urethane (UV cure coating) as the cure cycle was causing bubble entrapment.  Polyvinyl acetate (PVA) or viton is what is recommended for use with the Toluene and also works pretty well with the Xylene.