B737-300
Flight Crew Last 90 Days 230; Flight Crew Type 3600
Situational Awareness; Distraction; Confusion; Troubleshooting
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Weight And Balance
Flight Crew Diverted; General Declared Emergency
I was pilot monitoring in cruise flight at FL 350 headed when the Captain pointed out that my R1 windshield was arcing.  He instructed me to don my mask and get the checklist out. I was in the process of opening the Window Damage Checklist when I heard a loud bang and my windshield shattered/cracked in at least five places with numerous fingers from each. The Captain ordered me to declare an emergency and started slowing the airplane for a descent. I declared the emergency and told the Controller I needed a clearance to the nearest suitable airfield and an immediate descent. He cleared us direct to ZZZ and FL 290. We monitored the pressurization and had normal readings. We initiated the descent and as I was getting into the checklist; I loaded FMS landing data; and the Captain flew in that direction. I turned the seatbelt sign back on. The pilot flying communicated with the flight attendants and flew the airplane as I [restarted] the Window Damage Checklist. In the descent; I evaluated the window as possible outer pane cracks only. The Captain thought they were too severe to tell; but due to the severity of them and the fact he saw them arcing; we proceeded with our plan to divert. We lowered the landing gear and left the speedbrakes out to burn fuel for landing. I lowered my seat and put on sunglasses to help avoid debris in case the rest of the window gave way.We ran the QRH Checklist; the Descent Checklist; the Divert Checklist; loaded the box; ran the landing numbers; and flew to an overweight landing on Runway XXR and taxied to a gate. Touchdown fuel was 11.5; ZFW was 104943 giving us an overweight landing at 116.4 thousand pounds; performed with Captain's emergency authority
Directed the First Officer to don O2 mask and goggles as did I.
A B737 flight crew opted to descend and divert to a nearby airport when the First Officer's windshield first arced and then shattered. They were unable to determine with certainty whether the shattering was limited to the outer pane; a situation that would not have required such immediate action.