Types of glass can be broken down into 3 main categories and 4 further treatment subcategories. Different engineering practices are reflected in their ability to exhibit certain chemical, mechanical, thermal, and chemical properties. This creates variations in strength, transparency, and overall workability.
Glass is literally everywhere, and annually a minimum of 20 million TONNES of the stuff is manufactured. I don’t know about you, but I was curious as to what the heck are the differences between them! So come along, scroll on down and I’ll try to make this entirely bland topic slightly interesting.
The Three Exceptionally Exciting Types of Glass
1. Annealed Glass
This is the base product that is used to form the more advanced glass types that will follow this explanation. I’d like to call this type The Dummy Glass. It breaks into large and very dangerous jagged shards (it’s probably what’s used in dramatic Film Noire scenes).
All glass starts its life out as molten glass, and annealed glass cools very slowly until it reaches room temperature, which relieves any internal stresses. Without the cooling process, it would simply shatter and the tiniest of temperature changes. Great for dramatizing explosive emotional reactions, but not so great at keeping bugs out of your house once a light summer breeze destroys all your windows.
2. Heat Strengthened Glass
Also referred to as semi-toughened or semi-tempered, this is the product of when the annealed glass is heated back up to around 650-700 degrees Celsius. It is then cooled very quickly, which makes it twice as strong as annealed glass. It still breaks in comically dangerous shards, but it’s more likely to stick together.
3. Fully Tempered Glass
A step above the semi-stuff, this glass is all the way tempered, all the way toughened (just like Bane from Batman). It is evenly heated using conduction, convection, and radiation to 700 degrees Celsius. Then it is cooled by blasting all sides uniformly to create a greater surface and edge compression.
Since it’s blasted from both sides the cooling rate is different between the surface and the center. This creates different physical properties where compressive stresses on the surface are balanced by tensile stresses in the body of the glass sheet. Fully tempered glass is 5 times stronger and safer than annealed or heat-strengthened glass.
Its breakage pattern is in small and square fragments (once at a party, two dudes arm-wrestled on my glass coffee table and shattered it ((lol)) and it broke in this pattern! Nobody had a scratch even though it literally exploded into the hallway). This type of glass is well resistant to thermal stress and wind pressure.
The Four Thrilling Subcategories of Glass Types
1.1. Laminated Glass
Any of the 4 above types of glass can be laminated. It’s created by layering sheets of heat-treated glass with interlayers of polymeric material. Polymeric materials are macromolecules composed of dillions of repeated linked units. Needless to say, this stuff is ridiculously strong. Three examples of polymeric materials that are used in glass fabrication are polyvinyl butyral (PVB) and SentryGuard Plus (SGP), and cast-in-place (CIP).
Laminated glass has bullet-resistant capabilities (Elon Musk thought so too), fragment retention, sound dampening, ultraviolet filtering, and is resistant to fire. Upon impact, the outer layers of the sandwich may shatter, but the center polymeric material will hold!
PVB – pressure and heat are applied to this polymeric material between the two layers of glass on either side, compressing it all into one happy cohesive unit.
SGP – an interlayer that has 5 times the tear strength and 100 times the rigidity of the PVB layer (get it together PVB!) SGP is capable of withstanding violent storms, even hurricanes, and cyclones. I can imagine this is the only glass used in Florida homes.
CIP – or better known as resin lamination. This is done by holding two panels of glass very close to one another and then filling the tiny gap with liquid resin. It is then cured using UV radiation (like sticking your hand in that little purple box at the nail salon). This practice is used for unevenly surfaced glass, like car windows.
1.2. Insulated Glass
A similar starting point to laminated glass, but instead of filling the gap with resin, it’s filled with air or another noble gas (like argon) to influence the glass’ Ug value. Ug value is how quickly heat is able to transfer through a material.
This is a wonderful option for windows, and it’ll save you buckets of money in heating costs. The windows encourage heat gain in the winter, and heat loss in the summer. It repels UV rays and is very resistant to wind pressure. The insulated glass will keep your mocha hot and your mojito cold!
1.3. Coated Glass
Coated glass is manufactured for motif appearance, although it is usually scratch resistant and corrosion-resistant! The surface glass is exposed to vapor when it is still warm, which will then bind to the glass and form a permanent coating.
This stuff is highly durable and performs well in harsh weather conditions. It’s also the reason why people look like raccoons when they get back from a snowboarding trip, due to superb UV protection.
1.4. Acid-Etched Glass
And last but most certainly not least, we have glass that is chemically treated with an acidic material. The surface becomes distorted and results in a soft, matted, frosty appearance. This is made to diffuse light coming in through the glass and helps reduce glare.
Most commonly found in a classy bathroom shower separator, it’s a great option if you don’t want the option of looking out a window at the depressing world outside. (Sorry, I just watched the first of the presidential debates and………………)
FAQs
What type of glass is used in sunglasses?
Coated glass! It’s super resistant to corrosion and scratching and has impeccable UV radiation protection.
What type of glass is used for car windows?
Laminated glass. It’s extremely strong, so much so that when the glass is impacted, the two outer layers of glass crack, but the center polymeric layer remains intact. It’s the strongest and safest of the types of glasses.
What types of glass can be recycled?
All of them. Except for mirrors.
What type of glass is heat resistant?
Heat-strengthened and fully tempered glasses are far more resistant to heat than annealed glass. There are different ways that glass is treated further to increase heat resistance, although insulated treated glass is designed specifically with heat regulation in mind.
