Plexiglass is
acrylic and easy to bond to. Polycarbonate doesn't bond well to most common adhesives. Extruded
acrylic will easily fracture around drilled holes because of stresses that are locked in during
cooling from the extruder. These fractures can be dramatically reduced with heat, usually from a hydrogen flame. Some gas soldering tools have a suitable nozzle for hot air which works fairly well. Alternatively, use cast acrylic rather than extruded, as that doesn't have those inbuilt stresses, but may distort the view. Drill using a specially ground, zero-rake drill, and drill well oversize to allow for expansion/contraction.