The melting point of sapphire windows, also known as sapphire glass or alumina, is approximately 2040 degrees Celsius (3704 degrees Fahrenheit). Sapphire is a single crystal form of aluminum oxide (Al2O3) and has a high melting point due to its strong ionic bonds between aluminum and oxygen atoms.
Because of its high melting point, sapphire windows are capable of withstanding extremely high temperatures, making them suitable for use in high-temperature applications such as furnace windows, aerospace components, and high-pressure vessels.
Additionally, sapphire windows are also known for their exceptional hardness, durability, and scratch resistance, making them a popular choice for applications that require high optical clarity and resistance to wear and tear.