East Germany invented 'unbreakable' drinking glasses

Technology and Similar Products

• Superfest used ion-exchange toughening: replacing smaller sodium ions with larger potassium ions to create a compressive surface layer.
• Commenters note this is essentially the same principle as modern chemically strengthened glass (e.g., Gorilla Glass).
• Comparison with other toughened glassware: Duralex, Arcoroc, Corelle; generally considered durable, shatter into small pieces, and often used in restaurants and schools.
• Some point out that Superfest is more of a first-generation version of today’s tough glass rather than a “lost art.”

Durability, Failure Modes, and Safety

• Videos and anecdotes show “unbreakable” glasses still breaking, especially on hard or sharp materials; “shatter-resistant” is seen as more accurate than “unbreakable.”
• Tempered/chemically strengthened glass tends to fail catastrophically into many small pieces; some see this as safer (fewer sharp splinters), others emphasize cleanup difficulty and “exploding” behavior.
• Several users report extremely long-lived toughened glass in domestic use; others say breakage still occurs, especially in busy bar environments or with clumsy users/kids.

Economics and Market Adoption

• Debate over whether extra durability is a “big win”: if a glass costs much more but lasts only modestly longer, it may not be economical.
• Counterarguments highlight hidden costs: staff time, injuries, cleanup, lost product, and supply consistency for bars.
• Some are skeptical of the article’s claim that strong glasses failed purely because retailers profit from breakage, suggesting instead poor positioning, fashion changes, high energy/process cost, and post-reunification chaos in East German industry.

Recycling, Energy, and Sustainability

• Multiple comments note that many drinking glasses and cookware are not accepted in standard bottle-glass recycling streams due to different compositions and expansion coefficients.
• Borosilicate or alumino-silicate glasses are harder to recycle into ordinary containers; suggestions include downcycling into aggregates or fiberglass.
• Tension between durability (reduce/reuse) and recyclability: highly durable formulations often have higher energy cost and are harder to reprocess.
• Some argue glass is relatively benign in landfills; main environmental burden is energy-intensive production.

Side Discussions: Pubs, Hygiene, and Culture

• UK pint glass markings are explained as legal metrology (volume certification), not planned obsolescence.
• Heavy discussion of pub glass scratching, dishwashers, beer head quality, and differing beer cultures; relevance mainly to why bars might care about glass quality and replacement cycles.