An exterior rearview mirror assembly for a vehicle includes a base portion mounted to the vehicle and a movable portion that is pivotable relative to the base portion via a motor or motorized actuator or powerfold unit or the like. The structure has a stack of fiber-reinforced plies including first and second external plies which run from the first section into the second section on an inside and an outside of the corner, respectively. Methods of forming a bistable electro-optical device are also disclosed.