  We study the correlation functions of su(2) invariant spin-s chains in the
thermodynamic limit. We derive non-linear integral equations for an auxiliary
correlation function $\omega$ for any spin s and finite temperature T. For the
spin-3/2 chain for arbitrary temperature and zero magnetic field we obtain
algebraic expressions for the reduced density matrix of two-sites. In the zero
temperature limit, the density matrix elements are evaluated analytically and
appear to be given in terms of Riemann's zeta function values of even and odd
arguments.
