Remember that a thermal imaging camera is a device that detects temperature differences. It makes no difference whether you use it during the day or at night. If a target is heated to a different temperature than the outside environment, it will be visible through the scope lens. 
You can use the thermal scope https://www.atncorp.com/thermal-scope-thor-hd at dusk or dawn. It is unaffected by glare, unlike classic night vision devices. The advantage of thermal imaging scopes is that they do not need any external light sources: the thermal imaging sensor is sensitive to its own radiation of objects. As a result, these scopes work equally well during the day and at night, even in total darkness.