Yes, the form was sprayed with adhesive before placing the glass. On one peice I made a stencil to put the glue where I wanted, then placed the glass. The overage was easily vacuumed away. I did make sure to carefully place the concrete over the patterns. For the yin/yang I made a form using .025 aluminum to contain the glass, placed the concrete, vibrated, lifted out the aluminum form and pressed in the mesh. Next time I would probably use the epoxy over the deeper glass portion before grinding.
The inspiration for the jars was a piece I saw on the web using a wine bottle. I can't cut a wine bottle with my little wet saw so reached for something I could do for practice.