As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DEFECT 756210 - - - AT FL390 IN CRUISE FLIGHT, THE L1 FLIGHT DECK WINDOW BEGAIN ARCING. WE TURNED OFF L1 FWD WINDOW HEAT AND ARCING STOPPED TWO MINUTES LATER THE WINDOW CRACKED ON THE OUTER PANE. QRH COMPLETED. - - - RESOLUTION - (IN PROGRESS)