2,3,4,5,6-Pentafluorostyrene (PFS) was copolymerized with 1-vinylnaphathalene (1VN) in bulk by radical copolymerization at 25 degrees C (r1(VN)r(PFS) = 0.070) using t-butylperoxy pivalate as the inititator, at 70 degrees C (r(1VN)r(PFS) = 0.11.) using benzyol peroxide as the initiator, and at 120 degrees C (r(1VN)r(PFS) = 0.28) using t-butyl peroxide as the initiator; PFS was also copolymerized with 2-vinylnaphatbalene (2VN) in bulk by radical copolymerization at 70 degrees C (r(2VN)r(PFS) = 0.15) under similar conditions. Their reactivity ratios were determined at low monomer conversions using the nonlinear least-squares method of analysis, which demonstrated that both comonomer pairs tend to alternate, and that their alternating tendency increases with decreasing temperature, similar to the radical copolymerizations of PFS with styrene (St) in bulk. The glass transition temperatures determined by differential scanning calorimetry are elevated relative to their mole-average values, with the extent of elevation being greater for the 1VN-PFS copolymers than for the 2VN-PFS copolymers, which is greater than that for St-PFS copolymers. (C) 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 331-345, 2009