Turning a tree into glass may sound like magic, but creating transparent wood to replace the glass in your windows is something scientists have been working on for some years. This emergent wood-based glass substitute holds great potential as a more sustainable, durable, and thermally-efficient material for making windows as well as other applications.

Scientists at KTH Royal Institute of Technology have been at the forefront of this type of research, and in 2016 they unveiled their first transparent wood. That version relied on extracting lignin — a natural polymer that gives wood its color and strength — from the material, and filling the empty pores left behind with a synthetic polymer to provide transparency and rigidity.

More recently, however, the same team of scientists has found a more eco-friendly substitute, in a monomer made from a component found in citrus fruit peels called limonene. “The new limonene acrylate is made from renewable citruses, such as peel waste that can be recycled from the orange juice industry,” said study lead author, Ph.D. student Céline Montanari.

By filling the empty pores in the wood with the limonene-derived monomer, the scientists managed to achieve an impressive optical transmittance of 90 percent at 1.2 mm thick, and an incredibly low haze of 30 percent. The new version also exhibited remarkable rigidity and elasticity properties, which the researchers claim to make, is suitable for heavy-duty, structural uses.

According to the team, the sustainable transparent wood could eventually be used for a variety of purposes, including smart windows, wood with built-in lighting function, and wood for heat storage, which builds on their previous work.