Updated: Jul 30, 2020
No there isn't.
Roasting does not impact the level of caffeine in a coffee bean.
The amount of caffeine in a coffee bean only varies naturally, depending on the variety of coffee bean. e.g., Robusta coffee beans typically have twice the caffeine content than Arabica beans. Different Arabica variants have different caffeine content and so on.
That said, roasting does change the mass of a coffee bean.
So, if one makes coffee by measuring by volume, e.g. a tablespoon or coffee scoop, 1 tablespoon of lighter roast coffee will be more in mass than one tablespoon of darker roast of same coffee bean, hence the resultant cup will have slightly more caffeine than a darker roasted bean of the same variety.
If one makes coffee by weighing the dose, then a darker roast bean will be more in volume than a lighter roast and the resultant cup will have slightly more caffeine than a lighter roast one of same variety of coffee bean.