What was found
(CAN) BOTH WINDSHIELDS ON INNER SIDE FROSTED OVER, NORMALLY NOT A ISSUE BUT CREW NEEDED TO HAVE AN UNOBSTRUCTED VIEW TO BE ABLE TO DEVIATE AROUND CB`S WITH ASSOCIATED LIGHTENING WITH THE WEATHER RADAR AND ATC GUIDANCE. WINDSHIELD HEAT WAS SELECTED FROM WRM TO NORM TO CLEAR THE FROST. A FEW MINS LATER F/O NOTICED A BROWN LINE ON THE WINDSHIELD AT MID POINT LT TO RT THEN A LOUD POP AS THE WINDSHIELD OUT PANE SHATTERED. QRH WAS ACCOMPLISHED AND ATC WAS ADVISE FOR A LOWER ALTITUDE TO GET A LOWER DIFF. FLIGHT CONTINUED AS NORMAL AND LANDED UNEVENTFUL. UPON LANDING MAINTENANCE WAS NOTIFIED AND THE F/O WINDSHIELD WAS REPLACED.