B737 flight crew reported a flight deck window failed; resulting in a diversion.

Attributes
ACN	1685071
Time
Date	201909
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B737 Next Generation Undifferentiated
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Cockpit Window
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 164 Flight Crew Total 6225 Flight Crew Type 6225
Person 2
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 80 Flight Crew Total 10174 Flight Crew Type 10174
Events
Anomaly	Aircraft Equipment Problem Critical Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor

Narrative:

Just prior to top of descent; I noticed on the top center left area of window L1; a bright glowing light that intensified into arcing and would appear to emit a flame or spark. I asked the first officer to get the fire extinguisher ready and I donned my oxygen mask. Shortly thereafter; the window popped and shattered. I called for the window overheat QRH and [advised ATC]. After the situation stabilized; we advised ATC that no assistance was required and briefed the flight attendants; dispatch; and airport operations.

Original NASA ASRS Text

Title: B737 flight crew reported a flight deck window failed; resulting in a diversion.

Narrative: Just prior to Top of Descent; I noticed on the top center left area of window L1; a bright glowing light that intensified into arcing and would appear to emit a flame or spark. I asked the First Officer to get the fire extinguisher ready and I donned my oxygen mask. Shortly thereafter; the window popped and shattered. I called for the window overheat QRH and [advised ATC]. After the situation stabilized; we advised ATC that no assistance was required and briefed the Flight Attendants; Dispatch; and Airport Operations.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.