The heat capacity C-p(0) of glassy polyacenaphthylene has been determined using an adiabatic vacuum calorimeter between 6 and 338 K within about 0.2%. From the experimental data the thermodynamic functions C-p(0)(T), H-0(T)-H-0(0), S-0(T)-S-0(0), G(0)(T)-H-0(0) have been calculated over the range from 0 to 340 K. From literature data on the enthalpy of formation Delta(f)H(0) and the absolute entropy S-0(T) of the polymer obtained in the present work, the thermochemical characteristics for reaction of formation (entropy Delta(f)S(0), Gibbs energy Delta(f)G(0) and logarithm of thermodynamic equilibrium constant lg K-f(0)) of polyacenaphthylene in a glassy state from simple substances at T=298.15 K and standard pressure have been estimated, The results and the proper data for acenaphthylene have been used to calculate the thermodynamic quantities associated with polymerization of acenaphthylene Delta(pol)H(0)(T), Delta(pol)S(0)(T), Delta(pol)G(0)(T) into polyacenaphthylene from O to 340 K and of dehydrogenation of acenaphthene Delta(dehydr)H(0)(T). Delta(dehydr)S(0)(T), Delta(dehydr)G(0)(T) to acenaphthylene in the range from O to 350 K. The ceiling temperature T-ceil(0) of the polymerization process of acenaphthylene has been estimated.