A window assembly for a vehicle includes inner and outer window panels and a spacer element disposed between the window panels to establish an interpane cavity, with a roller shade disposed therein having an end fixedly attached at an anchor stop. A dielectric layer is disposed between the roller shade and a conductive layer at the inner window panel. The shade is operable via applying a voltage at the conductive layer and at the anchor stop to uncoil the shade from a coiled light transmitting condition to an at least partially uncoiled light attenuating condition. The window assembly may include conductive elements established at the dielectric layer for dissipating charge at the dielectric layer when the voltage is not applied and/or may mechanically retain the shade in its uncoiled state to allow for reduction in the voltage applied when the shade is uncoiled.