You must think that by now we know everything about glass. It’s been around for years, and it’s almost everywhere, in the walls of high-rise commercial buildings, in the windows of homes, in the vehicle, and aircraft windshields. Over the last year, the Industrial glass companies shipped out more than $28 billion in products in the United States. Yet through trial and error, the researchers and glassmakers are mutating Industrial glass composition to fine-tune its properties for different applications. Glass formulations may be built into specific materials to meet stringent demands for applications to come.
Some ways of enhancing these properties are:
- By changing the thermal expansion effect for production of labware glass
The effects of thermal expansion can be reduced by adding zinc oxide to silicate glass, which makes it thermal shock resistant. Glasses that use both borate and silicate as a former network, known as borosilicate glasses, are also thermally resistant and chemically durable. This makes them an appealing material for reaction vessels, test tubes, and other laboratory equipment.
- By varying the silicate content for the production of bioactive glass
The biomedical community is interested in a unique form of modified glass called bioactive glass. Interestingly, it closely emulates the mineral portion of living bone’s properties. This is exceptionally biocompatible and forms solid bone chemical bonds.
Calcium and sodium serve as the primary additives to produce a relatively soft glass of approximately 45% silicate. These glasses can be conveniently machined into implants for use in bone lesion repair.
- By altering zinc content for producing optical glass
Several glasses are highly prized for their unusual optical properties. Photochromic lenses mostly use zinc-modified glass while the photo-sensitive glass is made using silver, gold, and copper, and it can also change color in response to incident light.
- By varying chemical durability for manufacturing storage containers in the field of medicine
Glass’ chemical durability is usually lowered when elements, such as sodium and potassium, are used as additives. In contrast, glass’s chemical durability can be increased using alkaline earth metals, such as calcium.
- By varying resistivity of the glass
Glass finds application in resistors and condensers due to its high resistivity and permittivity. At low concentration, the resistivity of glasses can be significantly improved by adding oxides of tellurium, germanium, or titanium. It makes them appealing glass replacements for, for example, hearing aids and infrared detectors for ultra-high-resistance applications.
Modifiers are chemical substances that can be added in small amounts to the glass to further change its properties.
Types of Glass Modifiers
Lithia is a highly effective flux, mainly when used in conjunction with potash and feldspar soda. For other glasses with low thermal expansion, it is a beneficial constituent as it allows the overall alkali content to be low. Lithia-containing glasses are much more flexible in the molten state than those with a proportionate volume of sodium or potassium. It is beneficial in increasing and decreasing the viscosity of the glass without affecting its chemical and physical properties.
Lime provides stability, hardness, viscosity, strength, and ease of smelting and refining. Lime reduces the viscosity at high temperature but increases the working range “setting” rate. When present in amounts of more than 12.9 percent, lime significantly decreases the crushing force. Lime has the highest tensile strength when properly combined with soda and silica. It is used for producing rigid glass that is high in strength.
Effects of Glass Modifiers
Additive relationships loosely define properties of modified glass because glass typically behaves like a solution, implying that each component adds to the glass’s bulk properties by an amount approximately proportional to its concentration.
Glass modifiers interrupt the normal bonding between glass-forming elements and oxygen, as they bond loosely with oxygen atoms. Non-bridging oxygens are created, decreasing the relative amount of strong glass bonding.
This results in a drop in melting point, surface tension, and viscosity resulting from weaker overall bonding within the material. Glass modifiers influence the coefficient of thermal expansion, chemical resilience, and refractive index, making it easier to work with industrial glass at lower temperatures without any effect on transparency.
Some people have the notion that glass is an old-fashioned element as it has been used for millennia. But still, there are areas like energy generation and storage, more efficient buildings, biomedical components, delivery and communication of nanomedicines and information display technology, where understanding the potential properties of glass is still under work.