Two distinct glassy states formed by a thermotropic main-chain BB-3(1-Me) polyester were characterized by the wide-angle X-ray diffraction and DSC methods. In the BB-3(1-Me), a smectic CA liquid crystal (LC) was formed from an isotropic liquid on gradual cooling at rates smaller than 1 degreesC min(-1) and solidified without crystallization, resulting in the smectic LC glass. On the other hand, the isotropic liquid solidified without the liquid crystallization on rapid cooling at rates larger than 50 degreesC min(-1), resulting in the isotropic liquid glass. On heating, the smectic LC glass showed a glass transition (T-g(LC)) of 81 degreesC, while the isotropic liquid glass showed a glass transition (T-g(iso)) of 93 degreesC and transformed to the smectic LC at 110 C. The corresponding heat capacity increases were 50.1 and 78.5 J mol(-1) K-1 for the smectic LC glass and the isotropic liquid glass, respectively. The enthalpy-temperature relationship in all the states was estimated by integration of the heat capacity measured by the temperature-modulated DSC method. Temperature dependences of the enthalpy relaxation time of the two glasses obey the Vogel-Fulcher-Tamman (VFT) relationship and clearly show a single ideal glass temperature T-0(LC) (= 342 K) for the smectic LC, but two ideal glass temperatures T-0L(iso) (= 343 K) and T-0H(iso) (= 353 K) for the isotropic liquid. T-0L(iso) is 10 K lower than T-0H(iso) and corresponds to T-0(LC). According to a mode coupling theory of the glass transition of hard ellipsoid molecule liquid, the glass transition of the isotropic liquid at T-0L(iso) is associated with the freezing of translation molecular motions, while the transition at T-0H(iso) with the freezing of molecular orientation fluctuation. The correspondence of T-0(LC) to T-0L(iso) suggests that the glass transition of the smectic LC is dominated by the freezing of translation molecular motions in the smectic layer direction.