Shields. You've heard them mentioned before, right? TOS had tilt down shots into a transparent dome above the bridge -- yet no one complains about that (probably because Abrams didn't direct the episode).
Actual TREK canon has shown that when a weapon penetrates shields, the ship interior and crew are damaged or injured whether the weapon penetrates the hull or any other exterior surface.
Given the apparent properties of transparent aluminum and such inventions, my very first guess would be that a clear 'windshield' on the bridge would be made to specs just as sturdy as hull plating, and thus would be no more nor less vulnerable to attack than a solid section next to it.
Can't we assume this isn't a fragile plate glass window by the 23rd century?
MISSION:TREK's in-depth review of STAR TREK
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