Future optical backbone networks will be able to dynamically reconfigure optical connections in a few minutes and migrate the routes of existing connections with little service interruption at the IP layer, using the optical bridge-and-roll technique. A high data-rate dynamic wavelength service for these networks will provide more flexible connection services to customers. A customer owns or leases a few terminal ports in the network and is able to configure their connections freely between pairs of spare ports on demand. The carrier must provision enough resources in advance to accept any valid customer connection request. For mission critical services, connection interruptions are not allowed. In order to apply the dynamic services for these applications, the carrier must provide a non-volatile network such that the existing connections are not interrupted during reconfiguration of connection demands. This paper studies the volatility of optimal resource provisioning for dynamic wavelength services. We show that an optimal solution is volatile even if we use bridge-and-roll to migrate inappropriate routes. A non-volatile solution is then proposed at comparable cost for typical demands on a practical national core network.