The annihilation characteristics of the orthopositronium (o-Ps) in the structurally simplest elastomer cis-1,4-poly(butadiene) has been measured in the temperature range from 15 to 313 K and interpreted in the framework of the free volume concept. The temperature dependence of the mean lifetime of the o-Ps, tau(3), and its relative intensity, I-3, reflect a fine interplay between the free volume and microscopic chain dynamics. In addition to a pronounced break on the tau(3)-T plot at the glass transition temperature, T-g, a further two bends exist. The first, in glassy state, is relatively slight. The other one, in an elastic state, can be correlated with the melting temperature T-m of the crystalline phase. The order agreement between the temperature coefficients of free volume hole expansion a(h) and the mean square displacement of chain atoms alpha a(()[u2](>) from a recent neutron scattering study indicates a microscopic cause for the hole size growth with temperature. The decrease of I-3 with temperature T above 120 K correlates with the onset temperature of the so-called fast motion from neutron scattering measurements as well as with the so called Vogel temperature T-o for the primary segmental dynamics. The N-like shape course above T-g correlates with the cold crystallization from DSC measurements. In the melt region above 265 K, the slightly dependent tau(3) and I-3 quantities correspond to a formation of the bubble states of the o-Ps in the soft matrix. Finally, the temperature dependence of free volume hole distributions exhibits the essential changes from relative narrow distributions in the glassy state to wide distributions above T-g and ones that do not change much in the melt region of the polymer matrix.