  We show electric field control of the spin accumulation at the interface of
the oxide semiconductor Nb-SrTiO$_{3}$ with Co/AlO$_{x}$ spin injection
contacts at room temperature. The in-plane spin lifetime $\tau_\parallel$ as
well as the ratio of the out-of-plane to in-plane spin lifetime
$\tau_\perp/\tau_\parallel$ is manipulated by the built-in electric field at
the semiconductor surface, without any additional gate contact. The origin of
this manipulation is attributed to Rashba Spin-Orbit Fields (SOFs) at the
Nb-SrTiO$_3$ surface and shown to be consistent with theoretical model
calculations based on SOF spin flip scattering. Additionally, the junction can
be set in a high or low resistance state, leading to a non-volatile control of
$\tau_\perp/\tau_\parallel$, consistent with the manipulation of the Rashba SOF
strength. Such room temperature electric field control over the spin state is
essential for developing energy-efficient spintronic devices and shows promise
for complex oxide based (spin)electronics
