A perfluorinated polyimide comprising arepeating unit represented by general formula (1):(see fig. I)and a perfluorinated poly(amic acid) comprising arepeating unit represented by general formula (6):(see fig. II)wherein R1 is a tetravalent organic group; and R2 isa divalent organic group, provided that chemicalbonds between carbon atoms and monovalent elementscontained in R1 and R2 are exclusively carbon-to-fluorinebonds; methods for preparing them; andoptical material including the perfluorinatedpolyimide. 1,4-Bis(3,4-dicarboxytrifluorophenoxy)-tetrafluorobenzene dianhydride, 1,4-difluoropyro-melliticanhydride, 1,4-bis(3,4-dicarboxytrifluoro-phenoxy)tetrafluorobenzene, 1,4-difluoropyromelliticacid, and 1,4-bis(3,4-dicyanotrifluorophenoxy)tetra-fluorobenzene as well as methods preparing them. Theperfluorinated polyimide has a thermal stability andhas a low optical loss in an optical communicationwavelength region (0.8 to 1.7 µm).
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