The mechanical behavior of optical fiber as a function of dew point temperature

摘要

The dew point temperature (DPT) is defined as the temperature at which condensation will form from a gas containing moisture. The DPT, which is a measure of the water vapor reactivity, depends on the relative humidity (RH) and the temperature of the gas. The strength of optical fiber has been shown to have a dependence on the humidity and the temperature of the test environment. The results of one study imply that the strength over a range of temperature and humidity can be expressed as a function of the DPT only. While attractive for its simplicity, this idea suggests that the strength depends only on the thermodynamics of the equilibirum between the vapor and condensed phases of water and does not depend on the kinetics of the reaction between water and silica. In the work described here, the strength has been measured at various humidities and temperatures in order to test the dependence on dew point temperature. It was found that the strength degradation is not solely described by the DPT. The strength and dynamic fatigue data were also interpreted by a stress assisted chemical kinetics model. The degradation reaction order with respect to humidity at different air temperatures was found to be apprximately two.