  Triaxial neutron stars may be important sources of gravitational radiation
for the forthcoming generation of interferometric gravitational wave detectors
such as LIGO, VIRGO, and GEO600. We investigate the viscosity triggered bar
mode secular instability of rapidly rotating neutron stars by means of a
perturbation analysis of numerically constructed ``exact'' general relativistic
axisymmetric star models. In the theoretical approach, only the dominant parts
of the nonaxisymmetric terms of the 3D-Einstein equations are taken into
account. A comparison of our results with previous studies of Newtonian
polytropic stars confirms James' classical result gamma_crit=2.238 for the
critical polytropic index. Beyond the Newtonian regime, gamma_crit reveals a
slight increase toward highly relativistic configurations. Six out of twelve
employed realistic dense matter equations of state admit the spontaneous
symmetry breaking for masses above 1.6 M_sol.
