Daylight reflectance of partially fritted glasses

We have a detailed article on the testing procedures of partially fritted glass optical & thermal properties. For partially fritted glasses, the daylight reflectance property concerns many customers. This article aims to present some opinions from us on the daylight reflectance of partially fritted glasses.

Partially fritted glasses: glass or non-glass material?

If you are a textualist and adhere to the texts strictly, partially fritted glasses are obviously made of glass, as the word “glass” appears in the name, and you should stop reading this post from here.

If you are not a textualist and open to some discussions, below are some explanations on the differences between glass and non-glass materials in terms of optical characteristics.

There are 3 types of material surfaces, in terms of optical characteristics:

  • With specular reflectance only
  • With mixed reflection
  • With diffuse reflection only

In our opinion, conventional glasses and glasses with ceramic frit are distinct in optical characteristics. For a partially fritted glass, it is more reasonable to classify its clear part as glass material and classify its fritted part as non-glass material.

A surface with specular reflection only
Specular reflection only

Optical characteristics:

  • With specular reflection only
  • Diffuse reflection is negligible

For such materials:

  • Diffuse reflectance = 0%
  • Total reflectance = specular reflectance

Examples:

  • Conventional glasses
  • Materials with mirror finish
  • Metallic coating on glasses
A surface with mixed reflection
Mixed reflection

Optical characteristics:

  • With both specular reflection and diffuse reflection
  • Both components are not negligible

For such materials:

  • Total reflectance = diffuse reflectance + specular reflectance

Examples:

  • Most general facade and roof materials with certain glossiness
  • Glasses with ceramic frit
A surface with diffuse reflection only
Diffuse reflection only

Optical characteristics:

  • With diffuse reflection only
  • Specular reflection is negligible

For such materials:

  • Specular reflectance = 0%
  • Total reflectance = diffuse reflectance

Examples:

  • Materials with matt and rough surfaces: e.g. roof tiles, rough granites

Disclaimer

  • The information presented above is our opinion. It is not reviewed, agreed, or approved by any external parties.
  • For textualists, please do not read this post.

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