Glass can keep a drink safely contained, protect a smartphone screen, or serve as a foundation for electronic components. But when it comes to controlling heat, this familiar material still holds some scientific mysteries. Now, researchers have identified a key factor governing how efficiently heat travels through silicate glass, offering a new guideline for designing glass materials for next-generation electronic devices.

A research team led by Tohoku University investigated 13 different silicate glass compositions to understand how their thermal properties influence heat conduction. Their findings, published in Applied Physics Letters, reveal that the speed of sound through glass plays the dominant role in determining its thermal conductivity.

“Thermal conductivity has been studied for a long time, yet it remains one of the least understood properties of non-crystalline materials,” says Sohei Sukenaga, associate professor at Tohoku University.