Rewritable Glass Memory That Stores Data for Eons Without Power

By American Chemical SocietyFebruary 26, 2025

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A tiny cube of transparent glass holds these 3D designs that are revealed when exposed to specific lasers. 

Credit: Adapted from ACS Energy Letters 2025, DOI: 10.1021/acsenergylett.5c00024

Researchers have developed a new type of photochromic glass that can store and rewrite data indefinitely.

By embedding manganese and terbium, they’ve created a material that changes colors under different wavelengths of light, allowing for high-density, long-term storage without power. This breakthrough could revolutionize data preservation.
Exploring the Potential of Glass for Data Storage

For years, scientists have explored the potential of glass as a long-term data storage medium, drawn to its ability to preserve information for eons without requiring power. One promising candidate is photochromic glass, a special type of glass that changes color when exposed to different wavelengths of light. Now, researchers have developed a doped photochromic glass that can potentially store and rewrite data indefinitely, according to a study published today (February 26) in ACS Energy Letters.

How Photochromic Glass Could Revolutionize Data Storage

A familiar example of photochromism can be seen in certain eyeglasses that darken in sunlight and return to a clear state indoors, a process known as reversible photochromism. Similarly, some photochromic glass materials can change color based on specific wavelengths of light, making them an appealing, cost-effective option for high-density data storage. However, the challenge lies in not just encoding information but also being able to erase and rewrite it repeatedly.

Now, a research team led by Jiayan Liao, Ji Zhou, and Zhengwen Yang has made significant progress by developing reversible, tunable patterns in photochromic gallium silicate glass, bringing this futuristic technology one step closer to reality.

A new type of glass that’s etched with a bird design appears differently when exposed to different lasers. 

Credit: Adapted from ACS Energy Letters 2025, DOI: 10.1021/acsenergylett.5c00024

Developing a New Type of Doped Photochromic Glass

The team first designed gallium silicate glass modified with manganese and terbium ions by using a process called doped direct 3D lithography. Liao and the team used a green 532-nanometer (nm)-wavelength laser to inscribe 3D patterns into tiny slabs of the doped glass.

The intricate patterns, randomly chosen dots, symbols, QR codes, geometric prisms, and even a bird, appear purple in the transparent glass, which turns other colors when excited at precise wavelengths. Terbium luminesces green when excited by a deep violet 376 nm laser, and manganese luminesces red in the presence of violet light at 417 nm.

Then, to fully erase the patterns without changing the structure of the glass, the team applied heat at 1022 degrees Fahrenheit (550 degrees Celsius) for 25 minutes.

A Breakthrough in Rewritable Optical Memory

Furthermore, the researchers consider the use of manganese and terbium groundbreaking for their abilities to luminesce at distinctly different wavelengths, which makes it possible to get a tunable, multicolor readout of 3D patterns from a single material. The new approach could be used for high-capacity, stable 3D optical memory storage, and encryption in industrial, academic, and military applications.

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