A B757 FO'S FORWARD WINDOW BEGAN ARCING THEN DELAMINATED AND SHATTERED; OBSCURING VISION. AN EMER WAS DECLARED WITH A DIVERT TO A NEARBY ARPT.

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ENRTE AT FL370 THE CAPT AND I OBSERVED A LINE OF ARCING AND DELAMINATING ON THE LOWER PART OF THE FO F1 WINDOW MOVING FROM L TO R. THE ARCING AND DELAMINATION CONTINUED AND BEGAN TO FINGER OUT FROM THE LINE WHILE CONTINUING TO MOVE TO THE OUTSIDE R OF THE PANE. WE TURNED OFF WINDOW HEAT; DONNED OUR OXYGEN MASKS; REQUESTED A LOWER ALT; AND DECLARED AN EMER. WHILE IN THE PROCESS OF THESE ACTIONS THE WINDOW SHATTERED. WE REQUESTED VECTORS TO ZZZ -- WE WERE ABOUT 125 NM E OF THE ARPT AT THE TIME. I TURNED THE ACFT DIRECTLY TOWARDS ZZZ AND EXECUTED AS RAPID A DSCNT AS I COULD WHILE WORKING TO ALSO SLOW THE ACFT SPD TO REDUCE WINDOW STRESS. AS A FURTHER PRECAUTION TO THE OXYGEN MASK I ALSO DONNED MY SMOKE GOGGLES. THE CAPT REVIEWED THE QRH AND WORKED WITH OUR FAA JUMPSEATER SEARCHING FOR WINDOW HEAT/STRUCTURE CHKLIST ITEMS. I FLEW THE ACFT AND HANDLED COM WITH ATC. THE CAPT NOTIFIED THE CABIN CREW; OPS; AND THE PAX OF OUR SITUATION DURING THE DSCNT. DUE TO THE OBSCURED VIEW THROUGH THE SPIDER WEBBED GLASS ON MY SIDE OF THE COCKPIT WE TRANSITIONED CTL OF THE ACFT OVER TO THE CAPT FOR LNDG WHILE LEVEL AT 10000 FT. WE LANDED NORMALLY AT ZZZ JUST SLIGHTLY OVERWT (199300 LBS).