Graduate student Charles McLaren investigated the use of electric fields for glass forming that require softening. The study revealed the strong impact external electric fields can have on common alkali silicate glasses, including how the glasses show photoemission — pointing to a possible mechanism behind an electric field’s ability to speed up the softening process. McLaren’s advisor is Himanshu Jain.
The study involved creating a series of sodium-lithium alkali silicate glasses with varying ratios of lithium and sodium, which alter the electrical resistance of glass. Electrodes were attached to the samples, which were subjected to a 10 MPa load. As the glass was heated in a furnace, the team measured how different electric field strengths affected deformation or softening.
According to McLaren, their findings were quite stark. With no field, the sodium-containing glass typically softened just above 500°C. As voltage was ramped up, the furnace temperature needed to attain softening drastically decreased.
“It actually started happening below the glass transition stage, sometimes below 400 degrees,” McLaren said. The mixed alkali silicate glasses containing both lithium and sodium did not have quite as dramatic temperature lowering, but the effect still occurred, and in a predictable manner, one that could be fine-tuned for fabrication purposes, added Jain.