A product selected from the group consisting of:A. An acetylene end-capped polyimide oligomer having the structure: ##STR9## where R has the structure: ##STR10## ##STR11## where X is --CF2 --, or a bond, where R' is selected from the group consisting of a phenylene group, a naphthylene group, or ##STR12## where X is as defined above; and where R is an aryl group bearing a substituent having the s