Remove the glass from its frame.
Position the glass on mount that is perfectly level.
Measure the dimensions of the glass.
Clean the glass with a rubbing alcohol-soaked paper towel. This leaves it spotless and clean.
Cut a clear glass clad polycarbonate pane to the dimensions of the glass.
Carefully pour a liquid clear polyurethane epoxy on to the glass. It should spread smoothly and evenly. Put a drop cloth under the edges of the glass because the epoxy will spill over. Pour enough on so the entire pane is coated thoroughly.
Carefully place the glass-clad polycarbonate pane on top of the glass.
Align the edges of both panes. Let the epoxy run off. Allow the weight of the glass-clad polycarbonate to push the epoxy off.
After a minute wipe down the edges of the pane.
Wait for the epoxy to dry.