Most of the time leaf burn is due to heat from light being absorbed by leaves. If you put your hand in sunlight coming through a window you can feel the heat. Many sun blocking windows don't permit enough light to pass to warm a hand or leaf inside the window. I don't know whether your window is one of these. If your hand doesn't feel warmth from the sunlight it is not likely a leaf would burn.
__________________ May the bridges I've burned light my way.