In this paper, we have proposed a principle to design a compact and temperature independent electro-optic switch based on a slotted photonic crystal directional coupler (SPCDC). Infiltration of the slotted silicon photonic crystal with polymer enhances the slow light and decreases the switching length, whereas the different signs of thermo-optic coefficients of the polymer and silicon make the proposed switch stable within $25^{circ}C$ to $85^{circ}C$ temperature range. The SPCDC structure is modified to increase poling efficiency of the polymer in the slot and to flatten the dispersion diagram of the even mode to minimize the switching length.