Polarization modulators based on Liquid Crystal Variable Retarders (LCVRs) are envisaged as a powerful and versatile solution whose main advantage is the lack of mechanisms (i.e. rotating plates). An extensive test campaign has been carried out in order to demonstrate the feasibility of the LCVRs for the IMaX/SUNRISE magnetograph in environmental conditions similar to space conditions. Analysis of the influence of vacuum, temperature, vibration, gamma and ultraviolet radiation was performed by measuring the effects of these tests on the optical retardance, the response time, the wavefront distortion and the transmittance, including "in-situ" measurements. Outgassing rates of the different parts of the LCVRs were also studied. From the results obtained it can be concluded that these optical devices are suitable for SUNRISE and seem to be excellent candidates for aerospace missions as Solar Orbiter.