The constrained vapor bubble (CVB) is an excellent experimental setup for studying many interfacial science phenomena like spreading, wetting, evaporation from the contact line etc. Instabilities and oscillations have been observed at the contact line region of the evaporating meniscus. These oscillations start beyond a critical heat flux. We experimentally study the oscillations in a pentane meniscus on quartz substrate in a CVB. The film thickness, contact angle and curvature have been determined with great accuracy using recent advancements in interferomety techniques. The relationship of the adsorbed film thickness in front of the meniscus region, the contact angle of the liquid on the solid surface and the bulk curvature of the meniscus on the frequency of the oscillations have been examined. A model has been examined to describe the oscillations.