If you have a tri pod for your camera, you can take a photo of the glass by itself against any colored background, try a black background.
again use your tri pod for your actual shot. "whatever the glass is supposed to move across". table, counter, desk?
bring both clips into Vision Lab.
place the footage of the object that your glass will be sitting on, table, counter, daesk, onto the time line.
Then place the photo of the glass onto the time line.
add a chroma key to the photo and and key out the black, that way you can see through the glass.
you can animate the photo, scale the size up or down, the quad lets you move the entire photo around the canvas. take the "glass photo" and move it to the starting point of where you want it to move.
skip down the time line, however many frames you would like for the glass to move.
use the quad again to re position the glass photo from the starting point to where you want it to end up.
you can even add a displacement map on the glass with the vertical and horizontal settings rather low.
copy and paste the glass photo so you have another photo of the glass on the time line.
delete the displacement map from the second glass photo so that it reappears and slightly warps the table, counter, or desk footage as it travels across the surface.
hope that helps.