What was found
CREW REPORTED THAT DURING CRUISE, EN ROUTE TO BOS, THE F/O'S WINDOW MIDDLE PANE SHATTERED AND WAS ARCING. PER QRH CREW WAS TO DESCEND. DECLARED EMERGENCY TO EXPEDITE DESCENT. ONCE AT LOWER ALTITUDE CANCELLED EMERGENCY AND CONTINUED TO BOS, LANDING WITHOUT FURTHER EVENT. MAINTENANCE REMOVED AND REPLACED THE F/O'S WINDSHIELD AND THE WHC, RIGHT SIDE. REPORTED FOR PRECAUTIONARY PURPOSES, EMERGENCY WAS DECLARED DUE TO TRAFFIC IN AREA THEN EMERGENCY CANCELLED. COMPUTER, WINDOW HEAT; PN 416-00318-003; SN 4160031800264; MFG PPG; TT 9543; TC 3662; TSR 9543.