I used the following Terminal commands to disable animations:
# opening and closing Quick Look windows defaults write -g QLPanelAnimationDuration -float 0 # showing a toolbar or menu bar in full screen defaults write -g NSToolbarFullScreenAnimationDuration -float 0
from here: How to turn off all animations on OS X
Are there Terminal commands to re enable them, just in case?
Also, that link suggested TinkerTool, but which option in TinkerTool is for disabling the Quick Look animation?