An Airbus Industrie A320-211 operated by Air Canada and piloted by an airline transport pilot sustained minor damage at about 1045 Central time when the co-pilot’s window cracked during cruise at FL340. The flightcrew declared an emergency, diverted the flight and landed at Chicago O’Hare International Airport about 1113 without further incident. Visual conditions prevailed. There were no injuries to the two cockpit flightcrew members, three flight attendants, and 131 passengers.