Surface tension measurement of glass melts using sessile or pendant drop methods

The drop shape (sessile or pendant) method is widely used to measure the surface tension of glass melts. The accuracy of surface tension measurement has been improved by applying the technologies of video-image digitization and best-fitting algorithms. An accurate surface tension can be determined using hundreds of edge points from drop profiles and the best-fit with the drop profiles from the Young–Laplace equation. In this study, we examine the accuracy of measuring the surface tension of glass melts using the sessile or pendant drop methods. Experimental data show that the accuracy of surface tension measurement using the pendant drop method (±3 mN/m) is better than that obtained by using the sessile drop method (±9 to ±20 mN/m, depending on the contact angle).