There are two techniques and they are kind of opposite each other. The "Black Line" effect and the "White Line" effect.
Black line- surround the subject on three or four (top) sides with a white background material. For the cost and easy of use, 1/4 to 1/2 inch foam core or gator board works well. Make certain the back ground material does not touch in the corners to form, well, a corner, with about a one foot / 1/3 meter gap. These become light traps where the light will disappear. Light the White background material only (not the subject directly) making certain the corner light traps are not lit. If lit properly the main part of the glass will be white with an outline of black from the light traps.
White line effect- Make the background material Black and put white reflecting boards (more foam core) in the corners. Light the white reflectors, not the Black B/G. The effect will be a black/dark subject with a white outline.
For an example, check out the following link:
Lighting Glass
Add color B/G in the black line effect for even more fun!
Regards,