A crazed cabin window is the least of concerns when flying through volcanic ash.
An older technique for a volcanic ash encounter involved use of the Overheat Test button on the window heat panel, to shatter the outer panes of the forward cockpit windows to restore some visbility after being damaged by volcanic ash.
That had no effect on the cabin windows of course...but cabin windows are far down the priority chain if a volcanic ash encounter
The cabin windows crazing didn't happen immeditely while flying throught the volcanic ash cloud. The window crazing shows up weeks or months later. If it was not addressed the outer panes would fail. So to prevent failures aircraft that were exposed to the ash cloud would have all the cabin windows changed. When a operator has to replace more than 100 windows at $300 per window it becomes a real concern.