On entropy production in relativistic thermodynamics

Abstract. After to recall the energy-momentum tensor we will introduce the four vector current entropy density in which the entropy density is regarded as function of the energy density and of the symmetric strain tensor. By considering the concept of relativistic equilibrium state it will be de¯ned temperature in a generic inertial frame (no in proper frame) obtaining the transformation equations introduced by H. Ott for the tem- perature. Moreover, further considerations on the introduction of rela- tivistic stress tensor allows us to obtain the transformation equations for the strain tensor. Finally the time component of the derivative with re- spect to the coordinate of the four vector current entropy density will express the entropy balance and consequently the entropy production.