Other than letting it run. I will take a pitcher of warm water and splash it on the front sides and rear windows. It will often freeze but usually ends up defrosting quicker. If you wait for it to start to get warm inside it's more likely not to freeze.
i thought when you put warm or hot water on frozen glass the sudden temp change caused an uneven rate of expansion and caused the glass to crack sometimes?
If you had a chip or crack you might end up with a bigger crack. But it will not start one. The automotive glass is resilient and could put up with large temp swings.