When the idea for a year-long celebration of glass was first proposed in 2018, at the annual meeting of the International Commission on Glass (ICG) in Yokohama, Japan, few could have foreseen the global calamity that would soon befall. Barely 18 months later the COVID-19 pandemic had struck, and those proposing the year – most with day jobs in academia and industry – must have been tempted to put the project on the backburner. It’s fortunate that they still pushed ahead, as the International Year of Glass (IYOG2022) is exactly the sort of peaceful bridge-building initiative the world needs right now.

Like previous international years devoted to physics, light, astronomy and chemistry, this year’s celebrations are being held under the auspices of the United Nations (UN). Today, the UN exists to address global problems – be it climate change, energy, education or communication. Glass – a material that has played a pivotal role in shaping the modern world – also plays a vital part in solving some of these huge challenges. Indeed, glass-based technology is a crucial part of the UN’s 2030 sustainability goals, which address these and other interconnected issues – from clean water and sanitation, to industry, innovation and sustainable cities.

IYOG2022 can inform and remind people of the versatility of glassy materials and the enormous number of applications that arise as a consequence

John Parker, University of Sheffield, UK

The fact that glass is the source of so much innovation may not be immediately obvious. “Because glass is invisible it does not always get the visibility it deserves,” says Alicia Durán, a physicist at the Spanish Research Council in Madrid who is chair of the IYOG2022. “When you ask people about glass they often think of glassware and windows, they do not realize its importance in areas such as healthcare, telecommunications and energy. Glass is the invisible tool to build a more sustainable and fairer planet.”

Born in Argentina, Durán was a key player in boosting support for the IYOG2022 while serving as ICG president between 2018 and 2021 (see “How 2022 became the International Year of Glass” box). Her love for glass is equalled by her passion for connecting people and promoting gender equality in science. One of the key challenges for IYOG2022 organizers such as Durán is to get people to take a fresh view of a material that most of us have taken for granted throughout our entire lives.

Welcome to the age of glass

Glass has a long and rich history in shaping human society. Early humans used naturally occurring glass for jewellery, arrowheads and other tools, with archaeological evidence suggesting that the first societies to start making glass were in the Near East roughly 3500 years ago. Those people learned to heat crushed quartz in the presence of plant ash, which acted as a “flux” to reduce the melting temperature. By the Middle Ages, strong glasses coloured by metallic oxides adorned religious buildings from Europe to the Middle East.

Partially see-through windows have been around since Roman times, but flat transparent panes of glass truly proliferated after the invention of the “float glass” technique in the 1950s, in which a sheet of molten glass is spread over a bed of molten metal. Glass is also the material of optics. Eyeglasses have corrected the vision of billions, while mirrors and photography have changed the way we see ourselves, and microscopes and telescopes have revealed new, extraordinary worlds.

The IYOG2022’s central mantra is that we are living in an “age of glass” – a concept first introduced in a 2016 special issue of the Journal of Applied Glass Science. “Despite the shift to a digital world and the growing fascination with virtual reality, materials remain the building blocks of our society and culture,” argued glass scientists David Morse and Jeffrey Evenson in that issue. Indeed, they pointed out that glass innovation is accelerating – be it flexible glass that is slimmer than a bank note, bioactive glass that heals flesh wounds, or glass that can vitrify nuclear waste for long-term storage.

Perhaps glass rarely gets the limelight because it reliably underpins so many other new innovations. The obvious example is the Internet. Everyone lauds Tim Berners-Lee for inventing the World Wide Web and Steve Jobs for bringing it to our pockets, but far fewer people marvel at the fibre-optic cables that make computer networks a reality. Nanotechnology is another example. Graphene and other novel forms of carbon have grabbed headlines in recent years, but scientists and artisans have been manipulating glass at the nanoscale for centuries.

“Glass has come to be recognized as the quintessential nanotech material since it made possible the development of the Internet as we know it today, modern cell phones, photocopying and faxing machines,” says David Pye of Alfred University in the US, a former ICG president. “Add to this list a variety of medical procedures including endoscopic examinations, teeth and bone replacements, and specialized emplacement of radioactive glassy spheres to fight cancer in a highly directed, localized way.”

A recent example of glass ceding the limelight is the COVID-19 vaccine rollout from manufacturers such as Oxford–AstraZeneca and Pfizer–BioNTech. How many of us gave a moment’s thought to the glass containers that enabled the reliable and fast storage and delivery of the vaccines? Chemically resistant vials have advanced significantly in the past few years, and some can even support chemotherapy drugs with a pH up to 12. Likewise, foam-glass filters in glass drinks bottles can be used for affordable water purification to improve global sanitation.

Glass is also underappreciated in renewable energy and other green technologies. Glass surfaces are a key constituent in solar cells, and fibreglass is one of the principal materials for wind-turbine blades and building insulation. When it comes to sustainable materials in general, plastic alternatives – such as bamboo, hemp and beeswax – have become fashionable, but good old glass has been quietly carrying on as a non-toxic, infinitely recyclable material with a myriad of applications.

Re-energizing a glass culture

The IYOG2022 also hopes to bring a renewed focus on the close links between the art and science of glass making. Until recently, many university science labs had in-house glassblowing facilities for creating bespoke test tubes, beakers and other scientific glassware. But with glass production becoming increasingly commercial and mechanized, the international year is a chance to reconnect with the original essence of glassmaking. The IYOG2022 opening ceremony, for example, featured Japanese artist Kimiake Higuchi who uses pâte de verre, a technique whereby finely crushed glass is mixed with binding material and colouring agents to create a paste that is moulded and fired.

John Parker – emeritus professor of glass science at the University of Sheffield, UK, and chair of the IYOG2022 regional committee – is keen to underline the importance of glass to everyday life. “One reason behind the IYOG2022 is to inform and remind people of the versatility of glassy materials – their range of compositions, the possibilities for fabrication into so many different shapes, and the enormous number of applications it has as a consequence,” he says.

IYOG2022 is also a chance for glass experts to look outwards. Later this year, seven “glass wonders” from the worlds of art and architecture will be announced. An education programme will seek to inspire students, while cultural events will try to address gender balance in science and the needs of developing countries. In June, the Museum of Contemporary Art in Alcorcón, Spain is hosting “Women in Glass, Art and Science”, an event to highlight the contributions of women from Ibero-America. In September and October, the Pretoria Art Museum in South Africa will host “Fired Up” – an exhibition about the evolution of glassmaking in Africa.

Other events of note included a workshop in January on the reconstruction and conservation of glass fragments at the archaeological museum of the American University of Beirut in Lebanon that were shattered following the huge explosion at the port of Beirut in August 2020. Another poignant event was an online talk in April by Ukrainian glass artist Oksana Kondratyeva about the history of Ukrainian stained glass, with all proceeds going to the Disasters Emergency Committee’s Ukraine Appeal. An IYOG2022 seed fund has been launched to support any individuals and organizations with ideas for events.

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International Year of Glass gets cracking in Geneva

As with any one-off event, the challenge for those behind IYOG2022 is to create a legacy beyond the year itself. Organizers could take inspiration from the 2015 International Year of Light (IYL2015), which has fostered an annual International Day of Light on 16 May each year to celebrate the role of light in science, culture, education and sustainable development. John Dudley, the physicist who chaired IYL2015, says the year led to a lasting international outreach community, with students often telling him that they stayed in physics because of the IYL events in 2015. “I found a tremendous untapped reserve of enthusiasm and energy for public outreach within the scientific community,” he says.

The world is a more daunting place than it was four years ago when the IYOG2022 was first mooted. But with passion and a bit of luck regarding the pandemic, there is every chance that the year can inspire a new generation of glass enthusiasts across the world. When the IYOG2022’s closing ceremony takes place from 8–9 December in Tokyo, Japan, organizers will be hoping that they have evoked a renewed sense of wonder in a material that has repeatedly transformed the way we live.