Seeking simple circuit for converting 5vdc to ~15vac
Depending upon the AC current required by film, you MAY be able to use a MAX232 RS-232 driver chip to give you almost 20 Vp-p on the film. Initially, use a CMOS 555 timer chip as an oscillator. This will let you prove whether the RS-232 has sufficient drive.

If in fact the MAX-232 does work, you can probably persuade the MAX-232 to also be the oscillator. But no need to spend any time on that until you know that the MAX-232 will drive the film.