Electrochromic $WO_3$ thin films were prepared by electron beam deposition. The transmission and durability of films were investigated. Coloring and bleaching experiments were repeated in an electrolyte of propylene carbonate with 0.6M of $LiClO_4$ by cyclic voltammetry. Spectrophotometer was used to measure the transmission in the degraded films. The 5000 ${AA}$ thick film was found to be the stable after repeated cycles. The durability of the annealed film also showed improvements over unannealed samples. Tungsten oxide films with titanium content of about $10{sim}15$ mol% was found to be most stable, undergoing the least degradation during the repeated cycles.