I was thinking that but was concerned that there isn’t much surface area in the profile of the rims for the glue to purchase? I was wondering if there was some high-tech acrylic welding/melting?
I’ll try gluing the lens into the frame and the broken piece of frame to the lens.
Hence the suggestion to pin the joint mechanically. It isn't particularly easy to do, but it can be done. Are you anywhere near SE London?
Also, be careful of using superglue near the lens. The glue can bloom, and render the lens cloudy.
superglue?