Nowadays, eyeglass frames can be made from many materials. They mainly include plastics, metals as well as unusual materials such wood, leather or even stone. Plastics used to produce eyeglass frames include zylonite, cellulose acetate propionate, nylon, CR-39, polycarbonate as well as high index variations. Factors that can be used to assess these materials contain hypo-allergenic, lightweight, strong, flexible, corrosion-resistant, as well as color options. Within the large category of metal frame eyeglasses, possible materials contain Monel, titanium, beta-titanium, beryllium, stainless steel, aluminum and some other alloys. In similar, the aforementioned factors are also widely used to compare one metal with another. Along with the pervasive availability of lens options, there are actually many styles of eyeglasses for customers to choose from. But it seems that scientists are still making restless efforts in developing more materials for different industries including the eyewear industry. This trend has been testified by the creation of new forms of plastics such as polycarbonate and high index ones. Furthermore, it can also get proof from the wide collection of alloys that are being used in many fields. Memory metal eyeglasses are a perfect example.
In fact, many manufacturers are taking use of various alloys to produce eyeglass frames. Alloys simply mean that they are combined of more than one type of metal. It is widely known that alloys are usually developed by different factories in order to gain additional features that are unavailable from existing metals. Memory metal is one of the members among them. An explanation offered by Wikipedia says that memory metal is an alloy that “remembers” its original, cold, forged shape. It will return to that shape after being deformed by applying heat. As a result, memory metal is sometime also called a shape memory alloy. There are mainly three types of memory metals: copper-zinc-aluminum-nickel, copper-aluminum-nickel and nickel-titanium. Nowadays, these memory metals are also widely used in other applications, such as coffee pot thermostats, electrical connectors, deicing system, heat pipes, clamps and sculptures.
The special memory metal used in the eyeglass industry is actually nickel-titanium, which is the third type listed in the last paragraph. In the eyeglass world, this titanium-based alloy is called Flexon. These eyeglass frames can come back into the original shape even after twisting, bending and crushing. They also have features like lightweight, hypoallergenic and corrosion-resistant. In a word, memory metal eyeglasses are really unique.