On Thu, 14 Jul 2016 06:30:02 -0700 (PDT), wrote:

Plastic eyeglass frames are not typically made from this type of plastic. Try a good quality cyanoacrylate (crazy glue). I like Loctite 401 but there are lot of good ones out there.
For eyeclass frames I used to use Ambroid cement but thenew UV Cure
resin like the stuff from Kafuter works pretty good too. It leaves a
little lump, but it is crystal clear, so doesn't show up very much.