  It is recently shown that, besides the Schwarzshcild black hole solution,
there exist also scalarized black hole solutions in some
Einstein-scalar-Gauss-Bonnet theories. In this paper, we construct analytical
expressions for the metric functions and scalar field configurations for these
scalarized black hole solutions approximately by employing the continued
fraction parametrization method and investigate their thermodynamic stability.
It is found that the horizon entropy of a scalarized black hole is always
smaller than that of a Schwarzschild black hole, which indicates that these
scalarized black holes may decay to Schwarzschild black holes by emission of
scalar waves. This fact also implies the possibility to extract the energy of
scalar charges.
