A polarimetry capability has been added to the UCLA multichord far-infrared heterodyne interferometer system on TEXT-Upgrade. The polarimeter utilizes a phase technique in order to measure the Faraday rotation angle of the incident laser beam upon transmission through the plasma. From these data one derives information on the poloidal magnetic field, current density and safety factor profiles. The response of these profiles to electron cyclotron resonance heating and fast current ramps is investigated.